<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->
<!-- Created: Fri Apr 26 21:03:50 UTC 2024 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedBalanceSheet" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedBalanceSheet"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedBalanceSheet_Parentheticals" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedBalanceSheet_Parentheticals"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedIncomeStatement" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedIncomeStatement"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedIncomeStatement_Parentheticals" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedIncomeStatement_Parentheticals"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ShareholdersEquityType2or3" roleURI="http://www.bluewatervaccines.com/role/ShareholdersEquityType2or3"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ShareholdersEquityType2or3_Parentheticals" roleURI="http://www.bluewatervaccines.com/role/ShareholdersEquityType2or3_Parentheticals"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedCashFlow" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedCashFlow"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConsolidatedCashFlow_Parentheticals" roleURI="http://www.bluewatervaccines.com/role/ConsolidatedCashFlow_Parentheticals"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_OrganizationandBasisofPresentation" roleURI="http://www.bluewatervaccines.com/role/OrganizationandBasisofPresentation"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_GoingConcernandManagementsPlans" roleURI="http://www.bluewatervaccines.com/role/GoingConcernandManagementsPlans"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SummaryofSignificantAccountingPolicies" roleURI="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPolicies"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_BalanceSheetDetails" roleURI="http://www.bluewatervaccines.com/role/BalanceSheetDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_Acquisitions" roleURI="http://www.bluewatervaccines.com/role/Acquisitions"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SignificantAgreements" roleURI="http://www.bluewatervaccines.com/role/SignificantAgreements"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_NotesPayable" roleURI="http://www.bluewatervaccines.com/role/NotesPayable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SubscriptionAgreement" roleURI="http://www.bluewatervaccines.com/role/SubscriptionAgreement"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquity" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquity"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_CommitmentsandContingencies" roleURI="http://www.bluewatervaccines.com/role/CommitmentsandContingencies"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_RelatedPartyTransactions" roleURI="http://www.bluewatervaccines.com/role/RelatedPartyTransactions"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_IncomeTaxes" roleURI="http://www.bluewatervaccines.com/role/IncomeTaxes"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_RetirementPlans" roleURI="http://www.bluewatervaccines.com/role/RetirementPlans"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SubsequentEvents" roleURI="http://www.bluewatervaccines.com/role/SubsequentEvents"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_AccountingPoliciesByPolicy" roleURI="http://www.bluewatervaccines.com/role/AccountingPoliciesByPolicy"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SummaryofSignificantAccountingPoliciesTables" roleURI="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPoliciesTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_BalanceSheetDetailsTables" roleURI="http://www.bluewatervaccines.com/role/BalanceSheetDetailsTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_AcquisitionsTables" roleURI="http://www.bluewatervaccines.com/role/AcquisitionsTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SubscriptionAgreementTables" roleURI="http://www.bluewatervaccines.com/role/SubscriptionAgreementTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquityTables" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_IncomeTaxesTables" roleURI="http://www.bluewatervaccines.com/role/IncomeTaxesTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_RetirementPlansTables" roleURI="http://www.bluewatervaccines.com/role/RetirementPlansTables"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofRevenuebyGeographicalAreaTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofRevenuebyGeographicalAreaTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofLonglivedbyGeographicalAreaTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofLonglivedbyGeographicalAreaTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofActivityfortheSubscriptionAgreementLiabilityTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofActivityfortheSubscriptionAgreementLiabilityTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofActivityfortheContingentWarrantLiabilityTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofActivityfortheContingentWarrantLiabilityTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofComputationofDilutedSharesOutstandingTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofComputationofDilutedSharesOutstandingTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofInventoriesTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofInventoriesTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofPrepaidExpensesandOtherCurrentAssetsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofPrepaidExpensesandOtherCurrentAssetsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofIntangibleAssetsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofIntangibleAssetsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAnnualAmortizationExpenseTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAnnualAmortizationExpenseTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofGoodwillTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofGoodwillTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAccruedExpensesTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAccruedExpensesTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAggregateConsiderationTransferredfortheAssetsAcquiredTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAggregateConsiderationTransferredfortheAssetsAcquiredTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAssetsAcquiredTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAssetsAcquiredTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofFairValueoftheProteomedixStockOptionsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofFairValueoftheProteomedixStockOptionsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofConsolidatedStatementsofOperationsandComprehensiveLossTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofConsolidatedStatementsofOperationsandComprehensiveLossTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofFairValueofthePreferredInvestmentOptionsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofFairValueofthePreferredInvestmentOptionsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofValuationoftheContingentWarrantLiabilityTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofValuationoftheContingentWarrantLiabilityTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofOutstandingWarrantsExcludingContingentWarrantsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofOutstandingWarrantsExcludingContingentWarrantsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofStockOptionsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofStockOptionsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofFairValueofOptionsGrantedTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofFairValueofOptionsGrantedTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofUnvestedRestrictedStockTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofUnvestedRestrictedStockTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofStockBasedCompensationExpenseTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofStockBasedCompensationExpenseTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofLossBeforeIncomeTaxTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofLossBeforeIncomeTaxTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofDeferredTaxAssetsandLiabilitiesTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofDeferredTaxAssetsandLiabilitiesTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofIncomeTaxesDiffersfromtheStatutoryFederalRateTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofIncomeTaxesDiffersfromtheStatutoryFederalRateTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofUnrecognizedTaxBenefitsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofUnrecognizedTaxBenefitsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofComponentsofNetPeriodicBenefitCostTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofComponentsofNetPeriodicBenefitCostTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAccumulatedComprehensiveLossTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAccumulatedComprehensiveLossTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofAccompanyingConsolidatedBalanceSheetTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofAccompanyingConsolidatedBalanceSheetTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleoftheBeginningandEndingBalancesoftheAccumulatedBenefitObligationTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleoftheBeginningandEndingBalancesoftheAccumulatedBenefitObligationTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ScheduleofBenefitPaymentsTable" roleURI="http://www.bluewatervaccines.com/role/ScheduleofBenefitPaymentsTable"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_OrganizationandBasisofPresentationDetails" roleURI="http://www.bluewatervaccines.com/role/OrganizationandBasisofPresentationDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_GoingConcernandManagementsPlansDetails" roleURI="http://www.bluewatervaccines.com/role/GoingConcernandManagementsPlansDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SummaryofSignificantAccountingPoliciesDetails" roleURI="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPoliciesDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_BalanceSheetDetailsDetails" roleURI="http://www.bluewatervaccines.com/role/BalanceSheetDetailsDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_AcquisitionsDetails" roleURI="http://www.bluewatervaccines.com/role/AcquisitionsDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SignificantAgreementsDetails" roleURI="http://www.bluewatervaccines.com/role/SignificantAgreementsDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_NotesPayableDetails" roleURI="http://www.bluewatervaccines.com/role/NotesPayableDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SubscriptionAgreementDetails" roleURI="http://www.bluewatervaccines.com/role/SubscriptionAgreementDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4" roleURI="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_CommitmentsandContingenciesDetails" roleURI="http://www.bluewatervaccines.com/role/CommitmentsandContingenciesDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_RelatedPartyTransactionsDetails" roleURI="http://www.bluewatervaccines.com/role/RelatedPartyTransactionsDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_IncomeTaxesDetails" roleURI="http://www.bluewatervaccines.com/role/IncomeTaxesDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_RetirementPlansDetails" roleURI="http://www.bluewatervaccines.com/role/RetirementPlansDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#onco_r_SubsequentEventsDetails" roleURI="http://www.bluewatervaccines.com/role/SubsequentEventsDetails"/>
  <roleRef xlink:type="simple" xlink:href="onco-20231231.xsd#DocumentAndEntityInformation" roleURI="http://www.bluewatervaccines.com/role/DocumentAndEntityInformation"/>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedBalanceSheet">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfFinancialPositionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfFinancialPositionAbstract" xlink:to="us-gaap_StatementTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsCurrentAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AssetsCurrentAbstract" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Cash" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Cash"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_Cash" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsReceivableNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AccountsReceivableNetCurrent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_InventoryNet" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherReceivablesNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_OtherReceivablesNetCurrent" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrent" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidExpenseNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_PrepaidExpenseNoncurrent" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_DeferredCosts" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_Goodwill" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Assets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_Assets" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_LiabilitiesCurrentAbstract" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsPayableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsPayableCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_AccountsPayableCurrent" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_AccruedLiabilitiesCurrent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesPayableCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_NotesPayableCurrent" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_DerivativeLiabilitiesCurrent" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrent" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LongTermNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermNotesPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LongTermNotesPayable" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementLiabilityNoncurrent" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementLiabilityNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="SubscriptionAgreementLiabilityNoncurrent" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_DeferredIncomeTaxLiabilitiesNet" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Liabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Liabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_Liabilities" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingencies" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsAndContingencies"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommitmentsAndContingencies" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquityAbstract" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_PreferredStockValue" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_CommonStockValue" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapital" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapital"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_AdditionalPaidInCapital" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TreasuryStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_TreasuryStockValue" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquity" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MinorityInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_MinorityInterest" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedBalanceSheet_Parentheticals">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfFinancialPositionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfFinancialPositionAbstract" xlink:to="us-gaap_StatementTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="SeriesBConvertibleRedeemablePreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesBConvertibleRedeemablePreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesBConvertibleRedeemablePreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SeriesAConvertiblePreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesAConvertiblePreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesAConvertiblePreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="NotesPayableNetOfDebtDiscount" xlink:href="onco-20231231.xsd#onco_NotesPayableNetOfDebtDiscount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="NotesPayableNetOfDebtDiscount" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquityParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TemporaryEquityParOrStatedValuePerShare" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquitySharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TemporaryEquitySharesAuthorized" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquitySharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquitySharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TemporaryEquitySharesIssued" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquitySharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TemporaryEquitySharesOutstanding" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockSharesAuthorized" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockSharesIssued" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockSharesOutstanding" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockLiquidationPreferenceValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockLiquidationPreferenceValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockLiquidationPreferenceValue" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockSharesAuthorized" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockSharesIssued" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockSharesOutstanding" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TreasuryStockCommonShares" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TreasuryStockCommonShares" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedIncomeStatement">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_Revenues" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CostOfRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfRevenue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_CostOfRevenue" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GrossProfit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GrossProfit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_GrossProfit" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingExpensesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingExpensesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_OperatingExpensesAbstract" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_ResearchAndDevelopmentExpense" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OtherAssetImpairmentCharges" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingExpenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpenses" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_OperatingIncomeLoss" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIncomeAndExpensesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_OtherIncomeAndExpensesAbstract" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_InterestExpense" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="ChangeInFairValueOfSubscriptionAgreementLiability" xlink:href="onco-20231231.xsd#onco_ChangeInFairValueOfSubscriptionAgreementLiability"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="ChangeInFairValueOfSubscriptionAgreementLiability" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOptionChangesInFairValueGainLoss1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_FairValueOptionChangesInFairValueGainLoss1" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossAttributableToParent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_IncomeLossAttributableToParent" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="7.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_ProfitLoss" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockDividendsIncomeStatementImpact" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_PreferredStockDividendsIncomeStatementImpact" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasic"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_EarningsPerShareBasic" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTaxAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" xlink:to="us-gaap_ProfitLoss_0" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="ChangeInPensionBenefitObligation" xlink:href="onco-20231231.xsd#onco_ChangeInPensionBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" xlink:to="ChangeInPensionBenefitObligation" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherComprehensiveIncomeLossTaxAbstract" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedIncomeStatement_Parentheticals">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDiluted" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDiluted"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_EarningsPerShareDiluted" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ShareholdersEquityType2or3">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesBPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesBPreferredStockMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SeriesSeedMember" xlink:href="onco-20231231.xsd#onco_SeriesSeedMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesSeedMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesAPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesAPreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="3.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_PreferredStockMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_AdditionalPaidInCapitalMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TreasuryStockCommonMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_TreasuryStockCommonMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_RetainedEarningsMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ParentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ParentMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_ParentMember" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NoncontrollingInterestMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncontrollingInterestMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_NoncontrollingInterestMember" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="8.0"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementLineItems" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SharesOutstanding" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="IssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptions" xlink:href="onco-20231231.xsd#onco_IssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptions"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="IssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptions" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="us-gaap_StockIssuedDuringPeriodValueOther" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="us-gaap_StockIssuedDuringPeriodSharesOther" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueIssuanceOfSeriesAPreferredStock" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueIssuanceOfSeriesAPreferredStock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodValueIssuanceOfSeriesAPreferredStock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesIssuanceOfSeriesAPreferredStockinShares" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesIssuanceOfSeriesAPreferredStockinShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodSharesIssuanceOfSeriesAPreferredStockinShares" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodValueIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodValueAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodSharesAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" order="10.0" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <loc xlink:type="locator" xlink:label="OtherComprehensiveIncomeLossForeignCurrencyTranslationsAdjustmentTax" xlink:href="onco-20231231.xsd#onco_OtherComprehensiveIncomeLossForeignCurrencyTranslationsAdjustmentTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="OtherComprehensiveIncomeLossForeignCurrencyTranslationsAdjustmentTax" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueOfChangesInPensionBenefitObligation" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueOfChangesInPensionBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" xlink:to="StockIssuedDuringPeriodValueOfChangesInPensionBenefitObligation" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueOfssuanceOfCommonStockAndWarrants" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueOfssuanceOfCommonStockAndWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="StockIssuedDuringPeriodValueOfssuanceOfCommonStockAndWarrants" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrants" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrants" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodValueIssuanceofCommonStockandWarrantsinPrivatePlacement" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodValueIssuanceofCommonStockandWarrantsinPrivatePlacement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="StockIssuedDuringPeriodValueIssuanceofCommonStockandWarrantsinPrivatePlacement" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrantsInAugustPrivatePlacementNet" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrantsInAugustPrivatePlacementNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrantsInAugustPrivatePlacementNet" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ExerciseOfPrefundedWarrants" xlink:href="onco-20231231.xsd#onco_ExerciseOfPrefundedWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="ExerciseOfPrefundedWarrants" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ExerciseOfPrefundedWarrantsinShares" xlink:href="onco-20231231.xsd#onco_ExerciseOfPrefundedWarrantsinShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="ExerciseOfPrefundedWarrantsinShares" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PurchaseOfTreasuryShares" xlink:href="onco-20231231.xsd#onco_PurchaseOfTreasuryShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="PurchaseOfTreasuryShares" order="20.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="PurchaseOfTreasurySharesinShares" xlink:href="onco-20231231.xsd#onco_PurchaseOfTreasurySharesinShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="PurchaseOfTreasurySharesinShares" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ProfitLoss" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_0" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesOutstanding_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SharesOutstanding_0" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ShareholdersEquityType2or3_Parentheticals">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ParentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ParentMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_ParentMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="IssuanceOfCommonStockInInitialPublicOfferingNet" xlink:href="onco-20231231.xsd#onco_IssuanceOfCommonStockInInitialPublicOfferingNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="IssuanceOfCommonStockInInitialPublicOfferingNet" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IssuanceOfCommonStockAndWarrantsInAprilPrivatePlacementNet" xlink:href="onco-20231231.xsd#onco_IssuanceOfCommonStockAndWarrantsInAprilPrivatePlacementNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="IssuanceOfCommonStockAndWarrantsInAprilPrivatePlacementNet" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IssuanceOfCommonStockAndWarrantsInPrivatePlacementNet" xlink:href="onco-20231231.xsd#onco_IssuanceOfCommonStockAndWarrantsInPrivatePlacementNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems" xlink:to="IssuanceOfCommonStockAndWarrantsInPrivatePlacementNet" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedCashFlow">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfCashFlowsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_ProfitLoss" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_OtherAssetImpairmentCharges" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAdjustmentOfWarrants" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_FairValueAdjustmentOfWarrants" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AmortizationOfDebtDiscountPremium" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_ShareBasedCompensation" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges" order="6.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="GainLossOnRelatedPartyReceivable" xlink:href="onco-20231231.xsd#onco_GainLossOnRelatedPartyReceivable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="GainLossOnRelatedPartyReceivable" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryWriteDown" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryWriteDown"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_InventoryWriteDown" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DepreciationDepletionAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_DepreciationDepletionAndAmortization" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesFairValueAdjustment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueAdjustment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_LiabilitiesFairValueAdjustment" order="12.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdjustmentOfWarrantsGrantedForServices" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentOfWarrantsGrantedForServices"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentOfWarrantsGrantedForServices" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PensionExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_PensionExpense" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInInventories" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInInventories" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInOtherNoncurrentAssets" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInAccruedLiabilities" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireOtherProductiveAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireOtherProductiveAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_PaymentsToAcquireOtherProductiveAssets" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireRestrictedCertificatesOfDeposit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireRestrictedCertificatesOfDeposit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_PaymentsToAcquireRestrictedCertificatesOfDeposit" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireIntangibleAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_PaymentsToAcquireIntangibleAssets" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="ReceivableFromRelatedParties1" xlink:href="onco-20231231.xsd#onco_ReceivableFromRelatedParties1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="ReceivableFromRelatedParties1" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" order="5.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PaymentsForPurchaseOfTreasuryShares" xlink:href="onco-20231231.xsd#onco_PaymentsForPurchaseOfTreasuryShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="PaymentsForPurchaseOfTreasuryShares" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RepaymentsOfNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RepaymentsOfNotesPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_RepaymentsOfNotesPayable" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromStockOptionsExercised" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsForRepurchaseOfInitialPublicOffering" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForRepurchaseOfInitialPublicOffering"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_PaymentsForRepurchaseOfInitialPublicOffering" order="6.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfWarrants" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfWarrants" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsForRepurchaseOfPrivatePlacement" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForRepurchaseOfPrivatePlacement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_PaymentsForRepurchaseOfPrivatePlacement" order="8.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromWarrantExercises" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromWarrantExercises"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_ProceedsFromWarrantExercises" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_0" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncashInvestingAndFinancingItemsAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_NoncashInvestingAndFinancingItemsAbstract" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="EffectOfBusinessCombination" xlink:href="onco-20231231.xsd#onco_EffectOfBusinessCombination"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="EffectOfBusinessCombination" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConversionOfStockAmountIssued1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConversionOfStockAmountIssued1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="us-gaap_ConversionOfStockAmountIssued1" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOfAssetsAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOfAssetsAcquired"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="us-gaap_FairValueOfAssetsAcquired" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionPayablesAssumed1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncashOrPartNoncashAcquisitionPayablesAssumed1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="us-gaap_NoncashOrPartNoncashAcquisitionPayablesAssumed1" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RecognitionOfContingentWarrantLiabilityUponIssuanceOfCommonStockInPrivatePlacement" xlink:href="onco-20231231.xsd#onco_RecognitionOfContingentWarrantLiabilityUponIssuanceOfCommonStockInPrivatePlacement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="RecognitionOfContingentWarrantLiabilityUponIssuanceOfCommonStockInPrivatePlacement" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WarrantsIssuedForSettlementOfContingentWarrants" xlink:href="onco-20231231.xsd#onco_WarrantsIssuedForSettlementOfContingentWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="WarrantsIssuedForSettlementOfContingentWarrants" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="DeferredOfferingCostsPreviouslyPrepaid" xlink:href="onco-20231231.xsd#onco_DeferredOfferingCostsPreviouslyPrepaid"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="DeferredOfferingCostsPreviouslyPrepaid" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="Exerciseofprefundedwarrants" xlink:href="onco-20231231.xsd#onco_Exerciseofprefundedwarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="Exerciseofprefundedwarrants" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IssuanceOfRestrictedStock" xlink:href="onco-20231231.xsd#onco_IssuanceOfRestrictedStock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="IssuanceOfRestrictedStock" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RestrictedStockForfeitures" xlink:href="onco-20231231.xsd#onco_RestrictedStockForfeitures"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="RestrictedStockForfeitures" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PaymentOfAccruedBonusThroughRelatedPartyReceivable" xlink:href="onco-20231231.xsd#onco_PaymentOfAccruedBonusThroughRelatedPartyReceivable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="PaymentOfAccruedBonusThroughRelatedPartyReceivable" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:to="us-gaap_DebtConversionConvertedInstrumentAmount1" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConsolidatedCashFlow_Parentheticals">
    <loc xlink:type="locator" xlink:label="us-gaap_StatementOfCashFlowsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireProductiveAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireProductiveAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_PaymentsToAcquireProductiveAssets" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/OrganizationandBasisofPresentation">
    <loc xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/GoingConcernandManagementsPlans">
    <loc xlink:type="locator" xlink:label="GoingConcernAndManagementsPlansAbstract" xlink:href="onco-20231231.xsd#onco_GoingConcernAndManagementsPlansAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubstantialDoubtAboutGoingConcernTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubstantialDoubtAboutGoingConcernTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernAndManagementsPlansAbstract" xlink:to="us-gaap_SubstantialDoubtAboutGoingConcernTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPolicies">
    <loc xlink:type="locator" xlink:label="us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SignificantAccountingPoliciesTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_SignificantAccountingPoliciesTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/BalanceSheetDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisclosureTextBlockSupplementAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SupplementalBalanceSheetDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SupplementalBalanceSheetDisclosuresTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_SupplementalBalanceSheetDisclosuresTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/Acquisitions">
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SignificantAgreements">
    <loc xlink:type="locator" xlink:label="SignificantAgreementsAbstract" xlink:href="onco-20231231.xsd#onco_SignificantAgreementsAbstract"/>
    <loc xlink:type="locator" xlink:label="SignificantAgreementsTextBlock" xlink:href="onco-20231231.xsd#onco_SignificantAgreementsTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsAbstract" xlink:to="SignificantAgreementsTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/NotesPayable">
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayableAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesPayableAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NotesPayableAbstract" xlink:to="us-gaap_DebtDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SubscriptionAgreement">
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDisclosureAbstract" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDisclosureAbstract"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDisclosureTextBlock" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDisclosureAbstract" xlink:to="SubscriptionAgreementDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquity">
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="us-gaap_StockholdersEquityNoteDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/CommitmentsandContingencies">
    <loc xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/RelatedPartyTransactions">
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsAbstract" xlink:to="us-gaap_RelatedPartyTransactionsDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/IncomeTaxes">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxesPaidNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxesPaidNetAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="us-gaap_IncomeTaxDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/RetirementPlans">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SubsequentEvents">
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventsTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventsAbstract" xlink:to="us-gaap_SubsequentEventsTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/AccountingPoliciesByPolicy">
    <loc xlink:type="locator" xlink:label="us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UseOfEstimates" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UseOfEstimates"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_UseOfEstimates" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskCreditRisk" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskCreditRisk"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ConcentrationRiskCreditRisk" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentReportingPolicyPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_SegmentReportingPolicyPolicyTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeAndOtherAccountsReceivablePolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_TradeAndOtherAccountsReceivablePolicy" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_InventoryPolicyTextBlock" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AcquisitionsPolicyTextBlock" xlink:href="onco-20231231.xsd#onco_AcquisitionsPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="AcquisitionsPolicyTextBlock" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsFiniteLivedPolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_IntangibleAssetsFiniteLivedPolicy" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredChargesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredChargesPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_DeferredChargesPolicyTextBlock" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LesseeLeasesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeasesPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_LesseeLeasesPolicyTextBlock" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAccountingPolicyElectionMeasurementDatePolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccountingPolicyElectionMeasurementDatePolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_DefinedBenefitPlanAccountingPolicyElectionMeasurementDatePolicyTextBlock" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CollaborativeArrangementAccountingPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollaborativeArrangementAccountingPolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_CollaborativeArrangementAccountingPolicy" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRecognitionPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_RevenueRecognitionPolicyTextBlock" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpensePolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ResearchAndDevelopmentExpensePolicy" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsAndContingenciesPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_CommitmentsAndContingenciesPolicyTextBlock" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_IncomeTaxPolicyTextBlock" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComprehensiveIncomePolicyPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOfFinancialInstrumentsPolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_FairValueOfFinancialInstrumentsPolicy" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteRedeemablePreferredStockIssuePolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteRedeemablePreferredStockIssuePolicy"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_StockholdersEquityNoteRedeemablePreferredStockIssuePolicy" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="TreasuryStockPolicyPolicyTextBlock" xlink:href="onco-20231231.xsd#onco_TreasuryStockPolicyPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="TreasuryStockPolicyPolicyTextBlock" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerSharePolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_EarningsPerSharePolicyTextBlock" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" order="25.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPoliciesTables">
    <loc xlink:type="locator" xlink:label="us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/BalanceSheetDetailsTables">
    <loc xlink:type="locator" xlink:label="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisclosureTextBlockSupplementAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfInventoryCurrentTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_ScheduleOfInventoryCurrentTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfGoodwillTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_ScheduleOfGoodwillTextBlock" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/AcquisitionsTables">
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionContingentConsiderationTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionContingentConsiderationTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_AssetAcquisitionContingentConsiderationTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_AssetAcquisitionTableTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_ScheduleOfCondensedIncomeStatementTableTextBlock" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfCondensedIncomeStatementTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="srt_ScheduleOfCondensedIncomeStatementTableTextBlock" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SubscriptionAgreementTables">
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDisclosureAbstract" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDisclosureAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDisclosureAbstract" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityTables">
    <loc xlink:type="locator" xlink:label="us-gaap_EquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOptionQuantitativeDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_FairValueOptionQuantitativeDisclosuresTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ScheduleOfValuationOfTheContingentWarrantLiabilityTableTextBlock" xlink:href="onco-20231231.xsd#onco_ScheduleOfValuationOfTheContingentWarrantLiabilityTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="ScheduleOfValuationOfTheContingentWarrantLiabilityTableTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ScheduleOfFairValueOfOptionsGrantedIn2023And2022TableTextBlock" xlink:href="onco-20231231.xsd#onco_ScheduleOfFairValueOfOptionsGrantedIn2023And2022TableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="ScheduleOfFairValueOfOptionsGrantedIn2023And2022TableTextBlock" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquityAbstract" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/IncomeTaxesTables">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxesPaidNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxesPaidNetAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/RetirementPlansTables">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ScheduleOfAccompanyingConsolidatedBalanceSheetTableTextBlock" xlink:href="onco-20231231.xsd#onco_ScheduleOfAccompanyingConsolidatedBalanceSheetTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="ScheduleOfAccompanyingConsolidatedBalanceSheetTableTextBlock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_ScheduleOfCondensedFinancialStatementsTableTextBlock" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfCondensedFinancialStatementsTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="srt_ScheduleOfCondensedFinancialStatementsTableTextBlock" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofRevenuebyGeographicalAreaTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfRevenueByGeographicalAreaAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfRevenueByGeographicalAreaAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfRevenueByGeographicalAreaAbstract" xlink:to="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:to="srt_StatementGeographicalAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_SegmentGeographicalDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="country_US" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="country_US" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="country_CH" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="country_CH" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:to="us-gaap_EntityWideRevenueMajorCustomerLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:to="us-gaap_Revenues" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofLonglivedbyGeographicalAreaTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfLongLivedByGeographicalAreaAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfLongLivedByGeographicalAreaAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfLongLivedByGeographicalAreaAbstract" xlink:to="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="srt_StatementGeographicalAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_SegmentGeographicalDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="country_US" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="country_US" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="country_CH" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="country_CH" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NoncurrentAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncurrentAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="us-gaap_NoncurrentAssets" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfFairValueOfFinancialInstrumentsMeasuredOnARecurringBasisAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfFairValueOfFinancialInstrumentsMeasuredOnARecurringBasisAbstract"/>
    <loc xlink:type="locator" xlink:label="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" xlink:href="onco-20231231.xsd#onco_SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable"/>
    <loc xlink:type="locator" xlink:label="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems" xlink:href="onco-20231231.xsd#onco_SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfFairValueOfFinancialInstrumentsMeasuredOnARecurringBasisAbstract" xlink:to="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueInputsLevel1Member" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel2Member" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueInputsLevel2Member" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel3Member" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueInputsLevel3Member" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" xlink:to="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems" xlink:to="us-gaap_LiabilitiesAbstract" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAbstract" xlink:to="us-gaap_DerivativeLiabilitiesCurrent" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementLiabilityNoncurrent" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementLiabilityNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAbstract" xlink:to="SubscriptionAgreementLiabilityNoncurrent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAbstract" xlink:to="us-gaap_OtherLiabilitiesCurrent" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofActivityfortheSubscriptionAgreementLiabilityTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfActivityForTheSubscriptionAgreementLiabilityAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfActivityForTheSubscriptionAgreementLiabilityAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfActivityForTheSubscriptionAgreementLiabilityAbstract" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementLiabilityMember" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementLiabilityMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="SubscriptionAgreementLiabilityMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_0" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofActivityfortheContingentWarrantLiabilityTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfActivityForTheContingentWarrantLiabilityAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfActivityForTheContingentWarrantLiabilityAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfActivityForTheContingentWarrantLiabilityAbstract" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="ContingentWarrantLiabilityMember" xlink:href="onco-20231231.xsd#onco_ContingentWarrantLiabilityMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="ContingentWarrantLiabilityMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ReclassificationToEquity" xlink:href="onco-20231231.xsd#onco_ReclassificationToEquity"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="ReclassificationToEquity" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPeriodIncreaseDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPeriodIncreaseDecrease" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_0" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofComputationofDilutedSharesOutstandingTable">
    <loc xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDilutedOtherDisclosuresAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDilutedOtherDisclosuresAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EarningsPerShareDilutedOtherDisclosuresAbstract" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="StockOptionsMember" xlink:href="onco-20231231.xsd#onco_StockOptionsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="StockOptionsMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WarrantMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_WarrantMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RestrictedStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_RestrictedStockMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CommonStockIssuableUponConversionOfSeriesAPreferredStockMember" xlink:href="onco-20231231.xsd#onco_CommonStockIssuableUponConversionOfSeriesAPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="CommonStockIssuableUponConversionOfSeriesAPreferredStockMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofInventoriesTable">
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryNetAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryRawMaterials" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryRawMaterials"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InventoryNetAbstract" xlink:to="us-gaap_InventoryRawMaterials" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryWorkInProcess" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryWorkInProcess"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InventoryNetAbstract" xlink:to="us-gaap_InventoryWorkInProcess" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryFinishedGoods" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryFinishedGoods"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InventoryNetAbstract" xlink:to="us-gaap_InventoryFinishedGoods" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InventoryNetAbstract" xlink:to="us-gaap_InventoryNet" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofPrepaidExpensesandOtherCurrentAssetsTable">
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidInsurance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidInsurance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="us-gaap_PrepaidInsurance" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidRent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidRent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="us-gaap_PrepaidRent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PrepaidsResearchAndDevelopment" xlink:href="onco-20231231.xsd#onco_PrepaidsResearchAndDevelopment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="PrepaidsResearchAndDevelopment" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PrepaidProfessionalFees" xlink:href="onco-20231231.xsd#onco_PrepaidProfessionalFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="PrepaidProfessionalFees" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherPrepaidExpenseCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherPrepaidExpenseCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="us-gaap_OtherPrepaidExpenseCurrent" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrentAbstract" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofIntangibleAssetsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfIntangibleAssetsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfIntangibleAssetsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfIntangibleAssetsAbstract" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TradeNamesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeNamesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_TradeNamesMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DevelopedTechnologyRightsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_DevelopedTechnologyRightsMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_CustomerRelationshipsMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="CostBasisAbstract" xlink:href="onco-20231231.xsd#onco_CostBasisAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="CostBasisAbstract" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="FiniteLivedIntangibleAssetCost" xlink:href="onco-20231231.xsd#onco_FiniteLivedIntangibleAssetCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CostBasisAbstract" xlink:to="FiniteLivedIntangibleAssetCost" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ImpairmentOfIntangibleAssetExcludingGoodwill" xlink:href="onco-20231231.xsd#onco_ImpairmentOfIntangibleAssetExcludingGoodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CostBasisAbstract" xlink:to="ImpairmentOfIntangibleAssetExcludingGoodwill" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CostBasisAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CostBasisAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AccumulatedAmortizationAbstract" xlink:href="onco-20231231.xsd#onco_AccumulatedAmortizationAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="AccumulatedAmortizationAbstract" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccumulatedAmortizationAbstract" xlink:to="us-gaap_AmortizationOfIntangibleAssets" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="FiniteLivedIntangibleAssetsAccumulatedAmortizationEffectOfCurrencyTranslation" xlink:href="onco-20231231.xsd#onco_FiniteLivedIntangibleAssetsAccumulatedAmortizationEffectOfCurrencyTranslation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccumulatedAmortizationAbstract" xlink:to="FiniteLivedIntangibleAssetsAccumulatedAmortizationEffectOfCurrencyTranslation" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccumulatedAmortizationAbstract" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAnnualAmortizationExpenseTable">
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofGoodwillTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfGoodwillAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfGoodwillAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfGoodwillAbstract" xlink:to="us-gaap_Goodwill" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GoodwillTransfers" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillTransfers"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfGoodwillAbstract" xlink:to="us-gaap_GoodwillTransfers" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfGoodwillAbstract" xlink:to="us-gaap_GoodwillForeignCurrencyTranslationGainLoss" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Goodwill_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfGoodwillAbstract" xlink:to="us-gaap_Goodwill_0" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAccruedExpensesTable">
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract"/>
    <loc xlink:type="locator" xlink:label="AccruedResearchAndDevelopmentCurrent" xlink:href="onco-20231231.xsd#onco_AccruedResearchAndDevelopmentCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="AccruedResearchAndDevelopmentCurrent" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedUtilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedUtilitiesCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_AccruedUtilitiesCurrentAndNoncurrent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AccruedDeferredOfferingCosts" xlink:href="onco-20231231.xsd#onco_AccruedDeferredOfferingCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="AccruedDeferredOfferingCosts" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedProfessionalFeesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedProfessionalFeesCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_AccruedProfessionalFeesCurrentAndNoncurrent" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedMarketingCostsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedMarketingCostsCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_AccruedMarketingCostsCurrent" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_AccrualForTaxesOtherThanIncomeTaxesCurrent" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccruedLiabilitiesCurrentAndNoncurrentAbstract" xlink:to="us-gaap_AccruedLiabilitiesCurrent" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAggregateConsiderationTransferredfortheAssetsAcquiredTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfAggregateConsiderationTransferredForTheAssetsAcquiredAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfAggregateConsiderationTransferredForTheAssetsAcquiredAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionContingentConsiderationTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionContingentConsiderationTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfAggregateConsiderationTransferredForTheAssetsAcquiredAbstract" xlink:to="us-gaap_AssetAcquisitionContingentConsiderationTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionContingentConsiderationTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="FairValueConsiderationTransferredMember" xlink:href="onco-20231231.xsd#onco_FairValueConsiderationTransferredMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="FairValueConsiderationTransferredMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionContingentConsiderationTable" xlink:to="us-gaap_AssetAcquisitionAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionAxis" xlink:to="us-gaap_AssetAcquisitionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="AggregateConsiderationTransferredMember" xlink:href="onco-20231231.xsd#onco_AggregateConsiderationTransferredMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionAxis" xlink:to="AggregateConsiderationTransferredMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionContingentConsiderationTable" xlink:to="us-gaap_AssetAcquisitionLineItems" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferredOtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferredOtherAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_AssetAcquisitionConsiderationTransferredOtherAssets" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferredEquityInterestIssuedAndIssuable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferredEquityInterestIssuedAndIssuable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_AssetAcquisitionConsiderationTransferredEquityInterestIssuedAndIssuable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferredTransactionCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferredTransactionCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_AssetAcquisitionConsiderationTransferredTransactionCost" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferred" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferred"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_AssetAcquisitionConsiderationTransferred" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferredOther1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationConsiderationTransferredOther1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferredOther1" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAssetsAcquiredTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfAssetsAcquiredAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfAssetsAcquiredAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfAssetsAcquiredAbstract" xlink:to="us-gaap_AssetAcquisitionTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionTable" xlink:to="us-gaap_AssetAcquisitionAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="AssetsRecognizedMember" xlink:href="onco-20231231.xsd#onco_AssetsRecognizedMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionAxis" xlink:to="AssetsRecognizedMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionTable" xlink:to="us-gaap_AssetAcquisitionLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="AssetAcquisitionConsiderationTransferredInventory" xlink:href="onco-20231231.xsd#onco_AssetAcquisitionConsiderationTransferredInventory"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="AssetAcquisitionConsiderationTransferredInventory" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AssetAcquisitionConsiderationTransferredENTADFIIntangible" xlink:href="onco-20231231.xsd#onco_AssetAcquisitionConsiderationTransferredENTADFIIntangible"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="AssetAcquisitionConsiderationTransferredENTADFIIntangible" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferred" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferred"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionLineItems" xlink:to="us-gaap_AssetAcquisitionConsiderationTransferred" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofFairValueoftheProteomedixStockOptionsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfFairValueOfTheProteomedixStockOptionsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfFairValueOfTheProteomedixStockOptionsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfFairValueOfTheProteomedixStockOptionsAbstract" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockOptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockOptionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_StockOptionMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="srt_RangeAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="us-gaap_MeasurementInputTypeAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="MeasurementInputStockPriceMember" xlink:href="onco-20231231.xsd#onco_MeasurementInputStockPriceMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="MeasurementInputStockPriceMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputExpectedTermMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputExpectedTermMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputPriceVolatilityMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputPriceVolatilityMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputRiskFreeInterestRateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputRiskFreeInterestRateMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilityMeasurementInput" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilityMeasurementInput"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="us-gaap_DerivativeLiabilityMeasurementInput" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfEstimatedFairValuesOfAssetsAcquiredAndLiabilitiesAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfEstimatedFairValuesOfAssetsAcquiredAndLiabilitiesAbstract"/>
    <loc xlink:type="locator" xlink:label="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" xlink:href="onco-20231231.xsd#onco_AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable"/>
    <loc xlink:type="locator" xlink:label="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:href="onco-20231231.xsd#onco_AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfEstimatedFairValuesOfAssetsAcquiredAndLiabilitiesAbstract" xlink:to="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="BusinessAcquisitionMember" xlink:href="onco-20231231.xsd#onco_BusinessAcquisitionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" xlink:to="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightofUseAsset" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightofUseAsset"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightofUseAsset" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesCustomerRelationships" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesCustomerRelationships"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesCustomerRelationships" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProductRightsForDevelopedTechnology" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProductRightsForDevelopedTechnology"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProductRightsForDevelopedTechnology" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" order="11.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses" order="12.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" order="13.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" order="14.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPensionBenefitObligation" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPensionBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPensionBenefitObligation" order="15.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotePayable" xlink:href="onco-20231231.xsd#onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotePayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotePayable" order="16.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" order="17.0" preferredLabel="http://www.xbrl.org/2009/role/negatedTotalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" order="19.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofConsolidatedStatementsofOperationsandComprehensiveLossTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfConsolidatedStatementsOfOperationsAndComprehensiveLossAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfConsolidatedStatementsOfOperationsAndComprehensiveLossAbstract"/>
    <loc xlink:type="locator" xlink:label="srt_CondensedIncomeStatementTable" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CondensedIncomeStatementTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfConsolidatedStatementsOfOperationsAndComprehensiveLossAbstract" xlink:to="srt_CondensedIncomeStatementTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedIncomeStatementTable" xlink:to="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="ProteomedixMember" xlink:href="onco-20231231.xsd#onco_ProteomedixMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis" xlink:to="ProteomedixMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PMXTransactionMember" xlink:href="onco-20231231.xsd#onco_PMXTransactionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAxis" xlink:to="PMXTransactionMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedIncomeStatementTable" xlink:to="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" xlink:to="us-gaap_Revenues" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" xlink:to="us-gaap_ProfitLoss" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" xlink:to="us-gaap_BusinessAcquisitionsProFormaRevenue" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems" xlink:to="us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfAssumptionsUsedInMonteCarloModelWhichUtilizesLevel3InputsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfAssumptionsUsedInMonteCarloModelWhichUtilizesLevel3InputsAbstract"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssumptionForFairValueOnSecuritizationDateOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssumptionForFairValueOnSecuritizationDateOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfAssumptionsUsedInMonteCarloModelWhichUtilizesLevel3InputsAbstract" xlink:to="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel3Member" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueInputsLevel3Member" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" xlink:to="us-gaap_MeasurementInputTypeAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputExercisePriceMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputExercisePriceMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputExercisePriceMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputExpectedTermMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputExpectedTermMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputOptionVolatilityMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputOptionVolatilityMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputOptionVolatilityMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputRiskFreeInterestRateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputRiskFreeInterestRateMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" xlink:to="us-gaap_AssumptionForFairValueOnSecuritizationDateOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesLineItems" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilityMeasurementInput" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilityMeasurementInput"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssumptionForFairValueOnSecuritizationDateOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesLineItems" xlink:to="us-gaap_DerivativeLiabilityMeasurementInput" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofFairValueofthePreferredInvestmentOptionsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfFairValueOfThePreferredInvestmentOptionsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfFairValueOfThePreferredInvestmentOptionsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOptionQuantitativeDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOptionQuantitativeDisclosuresLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfFairValueOfThePreferredInvestmentOptionsAbstract" xlink:to="us-gaap_FairValueOptionQuantitativeDisclosuresTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresTable" xlink:to="us-gaap_AwardTypeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="OriginalMember" xlink:href="onco-20231231.xsd#onco_OriginalMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="OriginalMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ExchangedMember" xlink:href="onco-20231231.xsd#onco_ExchangedMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="ExchangedMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresTable" xlink:to="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueOptionQuantitativeDisclosuresLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofValuationoftheContingentWarrantLiabilityTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfValuationOfTheContingentWarrantLiabilityAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfValuationOfTheContingentWarrantLiabilityAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfValuationOfTheContingentWarrantLiabilityAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrivatePlacementMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_PrivatePlacementMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofOutstandingWarrantsExcludingContingentWarrantsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfOutstandingWarrantsExcludingContingentWarrantsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfOutstandingWarrantsExcludingContingentWarrantsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfOutstandingWarrantsExcludingContingentWarrantsAbstract" xlink:to="us-gaap_ClassOfWarrantOrRightTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightTable" xlink:to="us-gaap_ClassOfWarrantOrRightAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WarrantMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightAxis" xlink:to="us-gaap_WarrantMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightTable" xlink:to="us-gaap_ClassOfWarrantOrRightLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="8.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofStockOptionsTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfStockOptionsAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfStockOptionsAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfStockOptionsAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentRiskAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable" xlink:to="us-gaap_DerivativeInstrumentRiskAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockOptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockOptionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentRiskAxis" xlink:to="us-gaap_StockOptionMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueGranted" xlink:href="onco-20231231.xsd#onco_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueGranted"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueGranted" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" order="11.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueForfeitedCancelled" xlink:href="onco-20231231.xsd#onco_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueForfeitedCancelled"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueForfeitedCancelled" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="14.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofFairValueofOptionsGrantedTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfFairValueOfOptionsGrantedAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfFairValueOfOptionsGrantedAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfFairValueOfOptionsGrantedAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable" xlink:to="srt_RangeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofUnvestedRestrictedStockTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfUnvestedRestrictedStockAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfUnvestedRestrictedStockAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfUnvestedRestrictedStockAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementScenarioAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable" xlink:to="srt_StatementScenarioAxis" order="1.0"/>
    <loc xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="0.0"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="6.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<!-- [WMV5][XcpuxYn59dz7vgYynUDuwG7r97K2jUTysl7vcz0lJt/tSeJz73kx1cLt0ZFF2SK/vxBCY0vdSrb4i4f4wUs/dKlMHRtjt5HiP056YCLyrdSoyPYyQevay5dOg9LR2t/KvbZBYGbO0fRFqRMXruICW071VL4cva1Vo1fRqEHdR31R1aena1W/oLM7lTmOCBLWaZ9ZWyZBU9clRPWAm3ygSKlPhipMHX/wTZ1GpdAQuF5X0Rk/U0peMoZ1GlWBL0QwQ4YYjsaQQj5y1OiFHDkpk+TSIy2jKBgVC6BuLNzQw2d0OQvqtBvmxiw3I1GgCSekvILJhH3efW/iVkf2/SEYQBx37mpmy8k7] CSR-->
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofStockBasedCompensationExpenseTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfStockBasedCompensationExpenseAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfStockBasedCompensationExpenseAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfStockBasedCompensationExpenseAbstract" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ResearchAndDevelopmentMember" xlink:href="onco-20231231.xsd#onco_ResearchAndDevelopmentMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="ResearchAndDevelopmentMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofLossBeforeIncomeTaxTable">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofDeferredTaxAssetsandLiabilitiesTable">
    <loc xlink:type="locator" xlink:label="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsNetAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxAssetsNetAbstract" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsOther" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="LicenseAgreement" xlink:href="onco-20231231.xsd#onco_LicenseAgreement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="LicenseAgreement" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxAssetsGross" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxAssetsNet" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesNetAbstract"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesNetAbstract" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets" order="0.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilitiesOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesOther" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredIncomeTaxLiabilities" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="us-gaap_DeferredTaxLiabilities" order="5.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofIncomeTaxesDiffersfromtheStatutoryFederalRateTable">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationTaxCreditsResearch" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationTaxCreditsResearch"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationTaxCreditsResearch" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IncomeTaxReconciliationNondeductibleExpenseDerivativeLiability" xlink:href="onco-20231231.xsd#onco_IncomeTaxReconciliationNondeductibleExpenseDerivativeLiability"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="IncomeTaxReconciliationNondeductibleExpenseDerivativeLiability" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IncomeTaxReconciliationNondeductibleExpenseOfficersCompensation" xlink:href="onco-20231231.xsd#onco_IncomeTaxReconciliationNondeductibleExpenseOfficersCompensation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="IncomeTaxReconciliationNondeductibleExpenseOfficersCompensation" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationOtherReconcilingItems" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseStateRateAdjustment" xlink:href="onco-20231231.xsd#onco_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseStateRateAdjustment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseStateRateAdjustment" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationOtherAdjustments" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofUnrecognizedTaxBenefitsTable">
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefits" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefits" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefits_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefits_0" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccruedAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfBenefitObligationAndTheNetPeriodicBenefitCostAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfBenefitObligationAndTheNetPeriodicBenefitCostAbstract"/>
    <loc xlink:type="locator" xlink:label="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" xlink:href="onco-20231231.xsd#onco_RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable"/>
    <loc xlink:type="locator" xlink:label="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" xlink:href="onco-20231231.xsd#onco_RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfBenefitObligationAndTheNetPeriodicBenefitCostAbstract" xlink:to="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementScenarioAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" xlink:to="srt_StatementScenarioAxis" order="1.0"/>
    <loc xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="0.0"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" xlink:to="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" xlink:to="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" xlink:to="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" xlink:to="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofComponentsofNetPeriodicBenefitCostTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanServiceCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanServiceCost" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanInterestCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanInterestCost" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfComponentsOfNetPeriodicBenefitCostAbstract" xlink:to="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAccumulatedComprehensiveLossTable">
    <loc xlink:type="locator" xlink:label="ScheduleOfAccumulatedComprehensiveLossAbstract" xlink:href="onco-20231231.xsd#onco_ScheduleOfAccumulatedComprehensiveLossAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ScheduleOfAccumulatedComprehensiveLossAbstract" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementScenarioAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="srt_StatementScenarioAxis" order="1.0"/>
    <loc xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="0.0"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AmortizationOfNetGain" xlink:href="onco-20231231.xsd#onco_AmortizationOfNetGain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="AmortizationOfNetGain" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="EffectOfSettlement" xlink:href="onco-20231231.xsd#onco_EffectOfSettlement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="EffectOfSettlement" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTax" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RegulatedAndUnregulatedOperatingRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RegulatedAndUnregulatedOperatingRevenue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="us-gaap_RegulatedAndUnregulatedOperatingRevenue" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofAccompanyingConsolidatedBalanceSheetTable">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:to="us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:to="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:to="us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/negatedTotalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleoftheBeginningandEndingBalancesoftheAccumulatedBenefitObligationTable">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAbstract"/>
    <loc xlink:type="locator" xlink:label="srt_ScheduleOfCondensedFinancialStatementsTable" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <loc xlink:type="locator" xlink:label="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="srt_ScheduleOfCondensedFinancialStatementsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RetirementPlanTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ScheduleOfCondensedFinancialStatementsTable" xlink:to="us-gaap_RetirementPlanTypeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="AccumulatedBenefitObligationMember" xlink:href="onco-20231231.xsd#onco_AccumulatedBenefitObligationMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="AccumulatedBenefitObligationMember" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PlanAssetsMember" xlink:href="onco-20231231.xsd#onco_PlanAssetsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RetirementPlanTypeAxis" xlink:to="PlanAssetsMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ScheduleOfCondensedFinancialStatementsTable" xlink:to="srt_CondensedFinancialStatementsCaptionsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligation" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanServiceCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanServiceCost" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanInterestCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanInterestCost" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanActuarialGainLoss" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="DefinedBenefitPlanBenefitObligationOrdinaryContributionsPaidByEmployees" xlink:href="onco-20231231.xsd#onco_DefinedBenefitPlanBenefitObligationOrdinaryContributionsPaidByEmployees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="DefinedBenefitPlanBenefitObligationOrdinaryContributionsPaidByEmployees" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanOtherChanges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanOtherChanges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanOtherChanges" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanBenefitObligation_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanBenefitObligation_0" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanContributionsByEmployer" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="DefinedBenefitPlanPlanAssetsOrdinaryContributionsPaidByEmployees" xlink:href="onco-20231231.xsd#onco_DefinedBenefitPlanPlanAssetsOrdinaryContributionsPaidByEmployees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="DefinedBenefitPlanPlanAssetsOrdinaryContributionsPaidByEmployees" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" order="17.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanSettlementsPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanSettlementsPlanAssets" order="18.0" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CondensedFinancialStatementsCaptionsLineItems" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ScheduleofBenefitPaymentsTable">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:to="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:to="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/OrganizationandBasisofPresentationDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <loc xlink:type="locator" xlink:label="OrganizationandBasisofPresentationDetailsTable" xlink:href="onco-20231231.xsd#onco_OrganizationandBasisofPresentationDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="OrganizationandBasisofPresentationDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="OrganizationandBasisofPresentationDetailsTable" xlink:to="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_EquityMethodInvesteeNameDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="srt_EquityMethodInvesteeNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="OnconetixMember" xlink:href="onco-20231231.xsd#onco_OnconetixMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="OnconetixMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="OrganizationandBasisofPresentationDetailsTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IPOMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IPOMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_IPOMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_OwnershipAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_OwnershipAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="OrganizationandBasisofPresentationDetailsTable" xlink:to="srt_OwnershipAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_OwnershipDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_OwnershipDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_OwnershipAxis" xlink:to="srt_OwnershipDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ProteomedixMember" xlink:href="onco-20231231.xsd#onco_ProteomedixMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_OwnershipAxis" xlink:to="ProteomedixMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="OrganizationandBasisofPresentationDetailsTable" xlink:to="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="us-gaap_MinorityInterestOwnershipPercentageByParent" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ReclassificationsOfTemporaryToPermanentEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationsOfTemporaryToPermanentEquity"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="us-gaap_ReclassificationsOfTemporaryToPermanentEquity" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="InitialPublicOfferingShares" xlink:href="onco-20231231.xsd#onco_InitialPublicOfferingShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="InitialPublicOfferingShares" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PublicOfPerShare" xlink:href="onco-20231231.xsd#onco_PublicOfPerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="PublicOfPerShare" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConvertiblePreferredStockSharesReservedForFutureIssuance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockSharesReservedForFutureIssuance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="us-gaap_ConvertiblePreferredStockSharesReservedForFutureIssuance" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/GoingConcernandManagementsPlansDetails">
    <loc xlink:type="locator" xlink:label="GoingConcernAndManagementsPlansAbstract" xlink:href="onco-20231231.xsd#onco_GoingConcernAndManagementsPlansAbstract"/>
    <loc xlink:type="locator" xlink:label="GoingConcernandManagementsPlansDetailsTable" xlink:href="onco-20231231.xsd#onco_GoingConcernandManagementsPlansDetailsTable"/>
    <loc xlink:type="locator" xlink:label="GoingConcernandManagementsPlansDetailsLineItems" xlink:href="onco-20231231.xsd#onco_GoingConcernandManagementsPlansDetailsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernAndManagementsPlansAbstract" xlink:to="GoingConcernandManagementsPlansDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PrivatePlacementMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_PrivatePlacementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsTable" xlink:to="GoingConcernandManagementsPlansDetailsLineItems" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsLineItems" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromSaleOfOtherInvestments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsLineItems" xlink:to="us-gaap_ProceedsFromSaleOfOtherInvestments" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Cash" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Cash"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsLineItems" xlink:to="us-gaap_Cash" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WorkingCapitalDeficit" xlink:href="onco-20231231.xsd#onco_WorkingCapitalDeficit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsLineItems" xlink:to="WorkingCapitalDeficit" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RetainedEarningsAppropriated" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAppropriated"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="GoingConcernandManagementsPlansDetailsLineItems" xlink:to="us-gaap_RetainedEarningsAppropriated" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SummaryofSignificantAccountingPoliciesDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <loc xlink:type="locator" xlink:label="SummaryofSignificantAccountingPoliciesDetailsTable" xlink:href="onco-20231231.xsd#onco_SummaryofSignificantAccountingPoliciesDetailsTable"/>
    <loc xlink:type="locator" xlink:label="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:href="onco-20231231.xsd#onco_SummaryofSignificantAccountingPoliciesDetailsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="SummaryofSignificantAccountingPoliciesDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsTable" xlink:to="srt_RangeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsTable" xlink:to="SummaryofSignificantAccountingPoliciesDetailsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NumberOfOperatingSegments" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfOperatingSegments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_NumberOfOperatingSegments" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryValuationReserves" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InventoryValuationReserves"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_InventoryValuationReserves" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Depreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Depreciation"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_Depreciation" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_GoodwillImpairmentLoss" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RecognitionOfDeferredRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RecognitionOfDeferredRevenue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_RecognitionOfDeferredRevenue" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsReceivableNet" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsReceivableNet"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SummaryofSignificantAccountingPoliciesDetailsLineItems" xlink:to="us-gaap_AccountsReceivableNet" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/BalanceSheetDetailsDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisclosureTextBlockSupplementAbstract"/>
    <loc xlink:type="locator" xlink:label="BalanceSheetDetailsDetailsTable" xlink:href="onco-20231231.xsd#onco_BalanceSheetDetailsDetailsTable"/>
    <loc xlink:type="locator" xlink:label="BalanceSheetDetailsDetailsLineItems" xlink:href="onco-20231231.xsd#onco_BalanceSheetDetailsDetailsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureTextBlockSupplementAbstract" xlink:to="BalanceSheetDetailsDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ProteomedixMember" xlink:href="onco-20231231.xsd#onco_ProteomedixMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="ProteomedixMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="ENTADFIMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember_0" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="ENTADFIMember_0" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DevelopedTechnologyRightsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_DevelopedTechnologyRightsMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsTable" xlink:to="BalanceSheetDetailsDetailsLineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_AmortizationOfIntangibleAssets" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherCostOfOperatingRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherCostOfOperatingRevenue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_OtherCostOfOperatingRevenue" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherSellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherSellingGeneralAndAdministrativeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_OtherSellingGeneralAndAdministrativeExpense" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_AssetImpairmentCharges" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_OtherAssetImpairmentCharges" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedTradeNames" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedTradeNames"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="BalanceSheetDetailsDetailsLineItems" xlink:to="us-gaap_IndefiniteLivedTradeNames" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/AcquisitionsDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationsAbstract"/>
    <loc xlink:type="locator" xlink:label="AcquisitionsDetailsTable" xlink:href="onco-20231231.xsd#onco_AcquisitionsDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="AcquisitionsDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="AssetPurchaseAgreementMember" xlink:href="onco-20231231.xsd#onco_AssetPurchaseAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="AssetPurchaseAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="ENTADFIMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="MilestonePaymentsMember" xlink:href="onco-20231231.xsd#onco_MilestonePaymentsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="MilestonePaymentsMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PharmaceuticalServicesLLCMember" xlink:href="onco-20231231.xsd#onco_PharmaceuticalServicesLLCMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="PharmaceuticalServicesLLCMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ProteomedixMember" xlink:href="onco-20231231.xsd#onco_ProteomedixMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="ProteomedixMember" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="FairValueConsiderationTransferredMember" xlink:href="onco-20231231.xsd#onco_FairValueConsiderationTransferredMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="FairValueConsiderationTransferredMember" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="us-gaap_RelatedPartyTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ManagementServicesAgreementMember" xlink:href="onco-20231231.xsd#onco_ManagementServicesAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="ManagementServicesAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WraSerAPAMember" xlink:href="onco-20231231.xsd#onco_WraSerAPAMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="WraSerAPAMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="BankruptcyCourtMember" xlink:href="onco-20231231.xsd#onco_BankruptcyCourtMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="BankruptcyCourtMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WraSerMSAMember" xlink:href="onco-20231231.xsd#onco_WraSerMSAMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="WraSerMSAMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PMXTransactionMember" xlink:href="onco-20231231.xsd#onco_PMXTransactionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="PMXTransactionMember" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TradeNamesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeNamesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_TradeNamesMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_CustomerRelationshipsMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DevelopedTechnologyRightsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_DevelopedTechnologyRightsMember" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_DebtInstrumentAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember_0" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="ENTADFIMember_0" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="SeriesBConvertiblePreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesBConvertiblePreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesBConvertiblePreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesBPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesBPreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AcquisitionsDetailsTable" xlink:to="us-gaap_BusinessAcquisitionLineItems" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionDescriptionOfAcquiredEntity" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionDescriptionOfAcquiredEntity"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionDescriptionOfAcquiredEntity" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RoyaltySalesPercentage" xlink:href="onco-20231231.xsd#onco_RoyaltySalesPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="RoyaltySalesPercentage" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SalesPaymentsAmount" xlink:href="onco-20231231.xsd#onco_SalesPaymentsAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="SalesPaymentsAmount" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionProFormaInformationDescription" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionProFormaInformationDescription"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionProFormaInformationDescription" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregatePurchaseShares" xlink:href="onco-20231231.xsd#onco_AggregatePurchaseShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="AggregatePurchaseShares" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="BusinessTransactionYeare" xlink:href="onco-20231231.xsd#onco_BusinessTransactionYeare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="BusinessTransactionYeare" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="InventoryFairValue" xlink:href="onco-20231231.xsd#onco_InventoryFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="InventoryFairValue" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_AssetImpairmentCharges" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ImpairmentRate" xlink:href="onco-20231231.xsd#onco_ImpairmentRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="ImpairmentRate" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCosts" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="InitialPaymentAmount" xlink:href="onco-20231231.xsd#onco_InitialPaymentAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="InitialPaymentAmount" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="Payments" xlink:href="onco-20231231.xsd#onco_Payments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="Payments" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Deposits" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Deposits"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_Deposits" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashFDICInsuredAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashFDICInsuredAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_CashFDICInsuredAmount" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsForFees" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_PaymentsForFees" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="VotingInterestPercentage" xlink:href="onco-20231231.xsd#onco_VotingInterestPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="VotingInterestPercentage" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" xlink:href="onco-20231231.xsd#onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="NumberOfShares" xlink:href="onco-20231231.xsd#onco_NumberOfShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="NumberOfShares" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="RoyaltyRate" xlink:href="onco-20231231.xsd#onco_RoyaltyRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="RoyaltyRate" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WeightedAverageDiscountRate" xlink:href="onco-20231231.xsd#onco_WeightedAverageDiscountRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="WeightedAverageDiscountRate" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WeightedAverageDiscountRateThereafter" xlink:href="onco-20231231.xsd#onco_WeightedAverageDiscountRateThereafter"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="WeightedAverageDiscountRateThereafter" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueOfAssetsAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOfAssetsAcquired"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_FairValueOfAssetsAcquired" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InvestmentOwnedAtCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentOwnedAtCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_InvestmentOwnedAtCost" order="25.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SignificantAgreementsDetails">
    <loc xlink:type="locator" xlink:label="SignificantAgreementsAbstract" xlink:href="onco-20231231.xsd#onco_SignificantAgreementsAbstract"/>
    <loc xlink:type="locator" xlink:label="SignificantAgreementsDetailsTable" xlink:href="onco-20231231.xsd#onco_SignificantAgreementsDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsAbstract" xlink:to="SignificantAgreementsDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="OlogyBioservicesIncMember" xlink:href="onco-20231231.xsd#onco_OlogyBioservicesIncMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="OlogyBioservicesIncMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="CincinnatiChildrensHospitalMedicalCenterMember" xlink:href="onco-20231231.xsd#onco_CincinnatiChildrensHospitalMedicalCenterMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="CincinnatiChildrensHospitalMedicalCenterMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="OxfordUniversityInnovationLimitedMember" xlink:href="onco-20231231.xsd#onco_OxfordUniversityInnovationLimitedMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="OxfordUniversityInnovationLimitedMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="StJudeChildrensHospitalMember" xlink:href="onco-20231231.xsd#onco_StJudeChildrensHospitalMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="StJudeChildrensHospitalMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="UniversityOfTexasHealthScienceCenterAtSanAntonioMember" xlink:href="onco-20231231.xsd#onco_UniversityOfTexasHealthScienceCenterAtSanAntonioMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="UniversityOfTexasHealthScienceCenterAtSanAntonioMember" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CoDevelopmentAgreementMember" xlink:href="onco-20231231.xsd#onco_CoDevelopmentAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="CoDevelopmentAgreementMember" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="LaboratorCorporationOfAmericaMember" xlink:href="onco-20231231.xsd#onco_LaboratorCorporationOfAmericaMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="LaboratorCorporationOfAmericaMember" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsDetailsTable" xlink:to="us-gaap_DebtInstrumentAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="OUIAgreementMember" xlink:href="onco-20231231.xsd#onco_OUIAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="OUIAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="UTHealthAgreementMember" xlink:href="onco-20231231.xsd#onco_UTHealthAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="UTHealthAgreementMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="VendorAgreementMember" xlink:href="onco-20231231.xsd#onco_VendorAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="VendorAgreementMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquitySecuritiesByIndustryAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquitySecuritiesByIndustryAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsDetailsTable" xlink:to="us-gaap_EquitySecuritiesByIndustryAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquitySecuritiesIndustryMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquitySecuritiesIndustryMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquitySecuritiesByIndustryAxis" xlink:to="us-gaap_EquitySecuritiesIndustryMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="RegulatoryMilestonesMember" xlink:href="onco-20231231.xsd#onco_RegulatoryMilestonesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquitySecuritiesByIndustryAxis" xlink:to="RegulatoryMilestonesMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommercialAndIndustrialSectorMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquitySecuritiesByIndustryAxis" xlink:to="us-gaap_CommercialAndIndustrialSectorMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="DevelopmentMilestonesMember" xlink:href="onco-20231231.xsd#onco_DevelopmentMilestonesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EquitySecuritiesByIndustryAxis" xlink:to="DevelopmentMilestonesMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsDetailsTable" xlink:to="srt_RangeAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SignificantAgreementsDetailsTable" xlink:to="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="AggregateAgreementAmountInitialAgreement" xlink:href="onco-20231231.xsd#onco_AggregateAgreementAmountInitialAgreement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="AggregateAgreementAmountInitialAgreement" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanServiceCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_DefinedBenefitPlanServiceCost" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregateeAmount" xlink:href="onco-20231231.xsd#onco_AggregateeAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="AggregateeAmount" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CostPlusPercentage" xlink:href="onco-20231231.xsd#onco_CostPlusPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="CostPlusPercentage" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Assets"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_Assets" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_ResearchAndDevelopmentExpense" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsPayableCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_AccountsPayableCurrentAndNoncurrent" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CommercialSaleTerm" xlink:href="onco-20231231.xsd#onco_CommercialSaleTerm"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="CommercialSaleTerm" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RoyaltyNetSalesPercentage" xlink:href="onco-20231231.xsd#onco_RoyaltyNetSalesPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="RoyaltyNetSalesPercentage" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProductLiabilityContingencyAccrualDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductLiabilityContingencyAccrualDiscountRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_ProductLiabilityContingencyAccrualDiscountRate" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RoyaltyRates" xlink:href="onco-20231231.xsd#onco_RoyaltyRates"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="RoyaltyRates" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RevenueRate" xlink:href="onco-20231231.xsd#onco_RevenueRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="RevenueRate" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FeeIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FeeIncome"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_FeeIncome" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregateRoyaltiesAmount" xlink:href="onco-20231231.xsd#onco_AggregateRoyaltiesAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="AggregateRoyaltiesAmount" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DevelopmentCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopmentCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_DevelopmentCosts" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RoyaltyExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RoyaltyExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_RoyaltyExpense" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CostOfPropertyRepairsAndMaintenance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfPropertyRepairsAndMaintenance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_CostOfPropertyRepairsAndMaintenance" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfConsiderationReceived" xlink:href="onco-20231231.xsd#onco_PercentageOfConsiderationReceived"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="PercentageOfConsiderationReceived" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TaxesAndLicenses" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TaxesAndLicenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_TaxesAndLicenses" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CostMaintenance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostMaintenance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_CostMaintenance" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromLicenseFeesReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromLicenseFeesReceived"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_ProceedsFromLicenseFeesReceived" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AmountOfOtherPartyPayments" xlink:href="onco-20231231.xsd#onco_AmountOfOtherPartyPayments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="AmountOfOtherPartyPayments" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RoyaltiesPercentage" xlink:href="onco-20231231.xsd#onco_RoyaltiesPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="RoyaltiesPercentage" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFeeAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFeeAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_DebtInstrumentFeeAmount" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdministrativeFeesExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdministrativeFeesExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_AdministrativeFeesExpense" order="25.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LongTermDebtMaturityDate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturityDate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_LongTermDebtMaturityDate" order="26.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfessionalAndContractServicesExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfessionalAndContractServicesExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="us-gaap_ProfessionalAndContractServicesExpense" order="27.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="LicensedProductsPlusMilestonePaymentsDescription" xlink:href="onco-20231231.xsd#onco_LicensedProductsPlusMilestonePaymentsDescription"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ObligationWithJointAndSeveralLiabilityArrangementLineItems" xlink:to="LicensedProductsPlusMilestonePaymentsDescription" order="28.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/NotesPayableDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayableAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesPayableAbstract"/>
    <loc xlink:type="locator" xlink:label="NotesPayableDetailsTable" xlink:href="onco-20231231.xsd#onco_NotesPayableDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NotesPayableAbstract" xlink:to="NotesPayableDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementScenarioAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="srt_StatementScenarioAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_ScenarioUnspecifiedDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioUnspecifiedDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_ScenarioForecastMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioForecastMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_ScenarioForecastMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="us-gaap_DebtInstrumentAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="AssetPurchaseAgreementMember" xlink:href="onco-20231231.xsd#onco_AssetPurchaseAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="AssetPurchaseAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="NotePayableMember" xlink:href="onco-20231231.xsd#onco_NotePayableMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="NotePayableMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="ENTADFIMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesAPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesAPreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="us-gaap_AssetAcquisitionAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionAxis" xlink:to="us-gaap_AssetAcquisitionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ProteomedixAcquisitionMember" xlink:href="onco-20231231.xsd#onco_ProteomedixAcquisitionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetAcquisitionAxis" xlink:to="ProteomedixAcquisitionMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="us-gaap_MeasurementInputTypeAxis" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputTypeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputPriceVolatilityMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputPriceVolatilityMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputRiskFreeInterestRateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputRiskFreeInterestRateMember" order="2.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MeasurementInputExpectedTermMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputExpectedTermMember" order="3.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="NotesPayableDetailsTable" xlink:to="us-gaap_DebtInstrumentLineItems" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAnnualPrincipalPayment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAnnualPrincipalPayment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentAnnualPrincipalPayment" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentMaturityDate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentMaturityDate" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="PayableAverageDiscountRatePercentage" xlink:href="onco-20231231.xsd#onco_PayableAverageDiscountRatePercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="PayableAverageDiscountRatePercentage" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InterestExpenseDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_InterestExpenseDebt" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NotesPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_NotesPayable" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="DebtInstrumentDueDate" xlink:href="onco-20231231.xsd#onco_DebtInstrumentDueDate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="DebtInstrumentDueDate" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CashPaymentToTheSeller" xlink:href="onco-20231231.xsd#onco_CashPaymentToTheSeller"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="CashPaymentToTheSeller" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_PreferredStockSharesIssued" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtConversionOriginalDebtAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtConversionOriginalDebtAmount1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtConversionOriginalDebtAmount1" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilityMeasurementInput" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilityMeasurementInput"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DerivativeLiabilityMeasurementInput" order="13.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="DebtInstrumentDueTerm" xlink:href="onco-20231231.xsd#onco_DebtInstrumentDueTerm"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="DebtInstrumentDueTerm" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetAcquisitionPriceOfAcquisitionExpected" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionPriceOfAcquisitionExpected"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_AssetAcquisitionPriceOfAcquisitionExpected" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LongTermNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermNotesPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermNotesPayable" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SubscriptionAgreementDetails">
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDisclosureAbstract" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDisclosureAbstract"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDetailsTable" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDetailsTable"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementDetailsLineItems" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementDetailsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDisclosureAbstract" xlink:to="SubscriptionAgreementDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WarrantMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_WarrantMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsTable" xlink:to="SubscriptionAgreementDetailsLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="SaleOfUnits" xlink:href="onco-20231231.xsd#onco_SaleOfUnits"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="SaleOfUnits" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="us-gaap_SharesIssued" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockPricePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockPricePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="us-gaap_SaleOfStockPricePerShare" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ServicingLiabilityAtFairValueAdditions" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ServicingLiabilityAtFairValueAdditions"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="us-gaap_ServicingLiabilityAtFairValueAdditions" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ServicingLiabilityAtFairValueAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ServicingLiabilityAtFairValueAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="us-gaap_ServicingLiabilityAtFairValueAmount" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProductLiabilityContingencyThirdPartyRecoveryPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductLiabilityContingencyThirdPartyRecoveryPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubscriptionAgreementDetailsLineItems" xlink:to="us-gaap_ProductLiabilityContingencyThirdPartyRecoveryPercentage" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1">
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table" xlink:to="us-gaap_StatementClassOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="SeriesSeedPreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesSeedPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesSeedPreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesAPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesAPreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesBPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesBPreferredStockMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="SeriesAConvertiblePreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesAConvertiblePreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesAConvertiblePreferredStockMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table" xlink:to="us-gaap_StatementEquityComponentsAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_PreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1Table" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_CommonStockSharesAuthorized" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_CommonStockSharesIssued" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockSharesAuthorized" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockSharesIssued" order="5.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNotesPayable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_OtherNotesPayable" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockLiquidationPreference" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockLiquidationPreference" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SharesOfCommonStockRate" xlink:href="onco-20231231.xsd#onco_SharesOfCommonStockRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="SharesOfCommonStockRate" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleConversionPrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleConversionPrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockConvertibleConversionPrice" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleSharesIssuable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleSharesIssuable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart1LineItems" xlink:to="us-gaap_PreferredStockConvertibleSharesIssuable" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2">
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" xlink:to="us-gaap_StatementClassOfStockAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesBPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesBPreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="SeriesSeedPreferredStockMember" xlink:href="onco-20231231.xsd#onco_SeriesSeedPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="SeriesSeedPreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" xlink:to="us-gaap_StatementEquityComponentsAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_PreferredStockMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IPOMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IPOMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_IPOMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2Table" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleSharesIssuable" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleSharesIssuable"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_PreferredStockConvertibleSharesIssuable" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfIssuedOfCommonStock" xlink:href="onco-20231231.xsd#onco_PercentageOfIssuedOfCommonStock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="PercentageOfIssuedOfCommonStock" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfOutstandingOfCommonStock" xlink:href="onco-20231231.xsd#onco_PercentageOfOutstandingOfCommonStock"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="PercentageOfOutstandingOfCommonStock" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_PreferredStockSharesAuthorized" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_PreferredStockSharesIssued" order="5.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_PreferredStockSharesOutstanding" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleConversionPrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleConversionPrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_PreferredStockConvertibleConversionPrice" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfCumulativeDividends" xlink:href="onco-20231231.xsd#onco_PercentageOfCumulativeDividends"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="PercentageOfCumulativeDividends" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="NettingProceeds" xlink:href="onco-20231231.xsd#onco_NettingProceeds"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="NettingProceeds" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfOriginalIssuePrice" xlink:href="onco-20231231.xsd#onco_PercentageOfOriginalIssuePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="PercentageOfOriginalIssuePrice" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CumulativeDividends" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CumulativeDividends"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_CumulativeDividends" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DividendsPayableAmountPerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsPayableAmountPerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" xlink:to="us-gaap_DividendsPayableAmountPerShare" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3">
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="us-gaap_AwardTypeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RestrictedStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_RestrictedStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="HCWainwrightCoLLCMember" xlink:href="onco-20231231.xsd#onco_HCWainwrightCoLLCMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="HCWainwrightCoLLCMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="srt_RangeAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="us-gaap_StatementEquityComponentsAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="TreasuryStocksMember" xlink:href="onco-20231231.xsd#onco_TreasuryStocksMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="TreasuryStocksMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="April2022PrivatePlacementMember" xlink:href="onco-20231231.xsd#onco_April2022PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="April2022PrivatePlacementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AprilContingentWarrantsMember" xlink:href="onco-20231231.xsd#onco_AprilContingentWarrantsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="AprilContingentWarrantsMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="August2022PrivatePlacementMember" xlink:href="onco-20231231.xsd#onco_August2022PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="August2022PrivatePlacementMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AugustWainwrightWarrantsMember" xlink:href="onco-20231231.xsd#onco_AugustWainwrightWarrantsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="AugustWainwrightWarrantsMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AugustContingentWarrantsMember" xlink:href="onco-20231231.xsd#onco_AugustContingentWarrantsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="AugustContingentWarrantsMember" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3Table" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssued1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssued1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_StockIssued1" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockOtherSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockOtherSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_CommonStockOtherSharesOutstanding" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonUnitIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonUnitIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_CommonUnitIssued" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesIssuedPricePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesIssuedPricePerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_SharesIssuedPricePerShare" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfUnderwritingDiscount" xlink:href="onco-20231231.xsd#onco_PercentageOfUnderwritingDiscount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="PercentageOfUnderwritingDiscount" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherOwnershipInterestsOfferingCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherOwnershipInterestsOfferingCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_OtherOwnershipInterestsOfferingCosts" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightUnissued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightUnissued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightUnissued" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAdjustmentOfWarrants" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_FairValueAdjustmentOfWarrants" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_TreasuryStockAcquiredAverageCostPerShare" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_CommonStockSharesIssued" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleConversionPrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleConversionPrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_PreferredStockConvertibleConversionPrice" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="PlacementAgentFeeAndManagementFeePercentage" xlink:href="onco-20231231.xsd#onco_PlacementAgentFeeAndManagementFeePercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="PlacementAgentFeeAndManagementFeePercentage" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConversionOfStockSharesConverted1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConversionOfStockSharesConverted1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ConversionOfStockSharesConverted1" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregateNumberOfSharesPercenatge" xlink:href="onco-20231231.xsd#onco_AggregateNumberOfSharesPercenatge"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="AggregateNumberOfSharesPercenatge" order="25.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConversionOfStockSharesIssued1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConversionOfStockSharesIssued1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_ConversionOfStockSharesIssued1" order="26.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_OtherLiabilities" order="27.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CancelledPreferredInvestmentOptionsShares" xlink:href="onco-20231231.xsd#onco_CancelledPreferredInvestmentOptionsShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="CancelledPreferredInvestmentOptionsShares" order="28.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PrefundedWarrantsExercised" xlink:href="onco-20231231.xsd#onco_PrefundedWarrantsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="PrefundedWarrantsExercised" order="29.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockDividendsShares" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockDividendsShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_PreferredStockDividendsShares" order="30.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockConvertibleConversionPriceDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockConvertibleConversionPriceDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_PreferredStockConvertibleConversionPriceDecrease" order="31.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_PreferredStockSharesOutstanding" order="32.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherExpenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_OtherExpenses" order="33.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WarrantsIssuableUnderProvisionShares" xlink:href="onco-20231231.xsd#onco_WarrantsIssuableUnderProvisionShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="WarrantsIssuableUnderProvisionShares" order="34.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="IncreaseInTheFairValueOfThePreferredInvestmentOptions" xlink:href="onco-20231231.xsd#onco_IncreaseInTheFairValueOfThePreferredInvestmentOptions"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="IncreaseInTheFairValueOfThePreferredInvestmentOptions" order="35.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalOther"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" order="36.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ContingentWarrantLiabilityShares" xlink:href="onco-20231231.xsd#onco_ContingentWarrantLiabilityShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" xlink:to="ContingentWarrantLiabilityShares" order="37.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4">
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table"/>
    <loc xlink:type="locator" xlink:label="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:href="onco-20231231.xsd#onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_AwardTypeAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="MarketOfferingAgreementMember" xlink:href="onco-20231231.xsd#onco_MarketOfferingAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="MarketOfferingAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockOptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockOptionMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_StockOptionMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="UnvestedRestrictedStockMember" xlink:href="onco-20231231.xsd#onco_UnvestedRestrictedStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis" xlink:to="UnvestedRestrictedStockMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="InducementPIOSharesMember" xlink:href="onco-20231231.xsd#onco_InducementPIOSharesMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="InducementPIOSharesMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_TitleOfIndividualAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="srt_TitleOfIndividualAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_TitleOfIndividualWithRelationshipToEntityDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_ChiefExecutiveOfficerMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ChiefExecutiveOfficerMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_ChiefExecutiveOfficerMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="ChiefBusinessOfficerMember" xlink:href="onco-20231231.xsd#onco_ChiefBusinessOfficerMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis" xlink:to="ChiefBusinessOfficerMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_ChiefFinancialOfficerMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ChiefFinancialOfficerMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_ChiefFinancialOfficerMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_DirectorMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_DirectorMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis" xlink:to="srt_DirectorMember" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_WarrantMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_WarrantMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AugustContingentWarrantsMember" xlink:href="onco-20231231.xsd#onco_AugustContingentWarrantsMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="AugustContingentWarrantsMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_ClassOfWarrantOrRightAxis" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightAxis" xlink:to="us-gaap_ClassOfWarrantOrRightDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="WarrantInducementMember" xlink:href="onco-20231231.xsd#onco_WarrantInducementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightAxis" xlink:to="WarrantInducementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="April2022PrivatePlacementMember" xlink:href="onco-20231231.xsd#onco_April2022PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightAxis" xlink:to="April2022PrivatePlacementMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="August2022PrivatePlacementMember" xlink:href="onco-20231231.xsd#onco_August2022PrivatePlacementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfWarrantOrRightAxis" xlink:to="August2022PrivatePlacementMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="srt_RangeAxis" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="0.0"/>
    <loc xlink:type="locator" xlink:label="srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MinimumMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis" xlink:to="srt_MaximumMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_StatementEquityComponentsAxis" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_CommonStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PlanNameAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="us-gaap_PlanNameAxis" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="TwoThousandNinteenEquityIncentivePlanMember" xlink:href="onco-20231231.xsd#onco_TwoThousandNinteenEquityIncentivePlanMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="TwoThousandNinteenEquityIncentivePlanMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="TwoThousandTwentyTwoEquityIncentivePlanMember" xlink:href="onco-20231231.xsd#onco_TwoThousandTwentyTwoEquityIncentivePlanMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="TwoThousandTwentyTwoEquityIncentivePlanMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="TwoThousandTwentyTwoPlanMember" xlink:href="onco-20231231.xsd#onco_TwoThousandTwentyTwoPlanMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="TwoThousandTwentyTwoPlanMember" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="January2024Member" xlink:href="onco-20231231.xsd#onco_January2024Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="January2024Member" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="August2024Member" xlink:href="onco-20231231.xsd#onco_August2024Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="August2024Member" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="August2025Member" xlink:href="onco-20231231.xsd#onco_August2025Member"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="August2025Member" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PMXOptionPlanMember" xlink:href="onco-20231231.xsd#onco_PMXOptionPlanMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis" xlink:to="PMXOptionPlanMember" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4Table" xlink:to="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="SharesOfCommonStockIssued" xlink:href="onco-20231231.xsd#onco_SharesOfCommonStockIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="SharesOfCommonStockIssued" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="FixedCommissionRate" xlink:href="onco-20231231.xsd#onco_FixedCommissionRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="FixedCommissionRate" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockOptionExercisePriceIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockOptionExercisePriceIncrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_StockOptionExercisePriceIncrease" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockOptionExercisePriceDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockOptionExercisePriceDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_StockOptionExercisePriceDecrease" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregateNetProceeds" xlink:href="onco-20231231.xsd#onco_AggregateNetProceeds"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="AggregateNetProceeds" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockSharesSubscribedButUnissued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesSubscribedButUnissued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_CommonStockSharesSubscribedButUnissued" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfGrossProceeds" xlink:href="onco-20231231.xsd#onco_PercentageOfGrossProceeds"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="PercentageOfGrossProceeds" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LegalFees" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LegalFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_LegalFees" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherGeneralExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherGeneralExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_OtherGeneralExpense" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregatePurchaseShares" xlink:href="onco-20231231.xsd#onco_AggregatePurchaseShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="AggregatePurchaseShares" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfCommonStockShares" xlink:href="onco-20231231.xsd#onco_PercentageOfCommonStockShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="PercentageOfCommonStockShares" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="WarrantsIssuedForSettlementOfContingentWarrants" xlink:href="onco-20231231.xsd#onco_WarrantsIssuedForSettlementOfContingentWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="WarrantsIssuedForSettlementOfContingentWarrants" order="16.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FairValueAdjustmentOfWarrants" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_FairValueAdjustmentOfWarrants" order="17.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="18.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="19.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="20.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="21.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilities"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_OtherLiabilities" order="22.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ClassOfWarrantOrRightOutstanding" order="23.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="24.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharePrice" order="25.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_BusinessCombinationContingentConsiderationLiability" order="26.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" order="27.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" order="28.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="29.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" order="30.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="31.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="ExercisePrice" xlink:href="onco-20231231.xsd#onco_ExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="ExercisePrice" order="32.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="GrantDateFairValueOfStockOption" xlink:href="onco-20231231.xsd#onco_GrantDateFairValueOfStockOption"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="GrantDateFairValueOfStockOption" order="33.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" order="34.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" order="35.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings" order="36.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RestrictedSharesGrantedVestPercentage" xlink:href="onco-20231231.xsd#onco_RestrictedSharesGrantedVestPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="RestrictedSharesGrantedVestPercentage" order="37.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" order="38.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" order="39.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="40.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares" order="41.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="42.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" order="43.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="44.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" order="45.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" order="46.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" order="47.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesHeldInEmployeeStockOptionPlanAllocated" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesHeldInEmployeeStockOptionPlanAllocated"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_SharesHeldInEmployeeStockOptionPlanAllocated" order="48.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" order="49.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="50.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart4LineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" order="51.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/CommitmentsandContingenciesDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <loc xlink:type="locator" xlink:label="CommitmentsandContingenciesDetailsTable" xlink:href="onco-20231231.xsd#onco_CommitmentsandContingenciesDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherCommitmentsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="CommitmentsandContingenciesDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsandContingenciesDetailsTable" xlink:to="srt_StatementGeographicalAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_SegmentGeographicalDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="country_CH" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis" xlink:to="country_CH" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsandContingenciesDetailsTable" xlink:to="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis" xlink:to="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="SettlementAgreementMember" xlink:href="onco-20231231.xsd#onco_SettlementAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis" xlink:to="SettlementAgreementMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsandContingenciesDetailsTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IPOMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IPOMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_IPOMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsandContingenciesDetailsTable" xlink:to="us-gaap_OtherCommitmentsLineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LeaseCost"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_LeaseCost" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShortTermLeasePayments" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermLeasePayments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_ShortTermLeasePayments" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsForRent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForRent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_PaymentsForRent" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLeaseIncomeLeasePayments" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLeaseIncomeLeasePayments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_OperatingLeaseLeaseIncomeLeasePayments" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FeeIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FeeIncome"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_FeeIncome" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LegalFees" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LegalFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_LegalFees" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesIssued"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_SharesIssued" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_ClassOfWarrantOrRightOutstanding" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherSellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherSellingGeneralAndAdministrativeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_OtherSellingGeneralAndAdministrativeExpense" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="PercentageOfSubscription" xlink:href="onco-20231231.xsd#onco_PercentageOfSubscription"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="PercentageOfSubscription" order="10.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AggregatePayments" xlink:href="onco-20231231.xsd#onco_AggregatePayments"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="AggregatePayments" order="11.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees" order="12.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LaborAndRelatedExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LaborAndRelatedExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_LaborAndRelatedExpense" order="13.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DividendsPaidinkind" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsPaidinkind"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_DividendsPaidinkind" order="14.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherExpenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OtherCommitmentsLineItems" xlink:to="us-gaap_OtherExpenses" order="15.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/RelatedPartyTransactionsDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsAbstract"/>
    <loc xlink:type="locator" xlink:label="RelatedPartyTransactionsDetailsTable" xlink:href="onco-20231231.xsd#onco_RelatedPartyTransactionsDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsAbstract" xlink:to="RelatedPartyTransactionsDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RelatedPartyTransactionsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RelatedPartyTransactionsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="us-gaap_RelatedPartyTransactionDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="CEOMember" xlink:href="onco-20231231.xsd#onco_CEOMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="CEOMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="CBOMember" xlink:href="onco-20231231.xsd#onco_CBOMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="CBOMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RelatedPartyTransactionsDetailsTable" xlink:to="us-gaap_DebtInstrumentAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="NonConvertibleDebentureMember" xlink:href="onco-20231231.xsd#onco_NonConvertibleDebentureMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="NonConvertibleDebentureMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="RelatedPartyTransactionsDetailsTable" xlink:to="us-gaap_RelatedPartyTransactionLineItems" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsForFees" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForFees"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_PaymentsForFees" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_RelatedPartyTransactionAmountsOfTransaction" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherReceivables" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherReceivables"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OtherReceivables" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherReceivablesNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OtherReceivablesNetCurrent" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RepaymentsOfRelatedPartyDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RepaymentsOfRelatedPartyDebt"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_RepaymentsOfRelatedPartyDebt" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="MiscellaneousExpenses" xlink:href="onco-20231231.xsd#onco_MiscellaneousExpenses"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="MiscellaneousExpenses" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementPMXInvestorPercentage" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementPMXInvestorPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="SubscriptionAgreementPMXInvestorPercentage" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAnnualPrincipalPayment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAnnualPrincipalPayment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DebtInstrumentAnnualPrincipalPayment" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/IncomeTaxesDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxesPaidNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxesPaidNetAbstract"/>
    <loc xlink:type="locator" xlink:label="IncomeTaxesDetailsTable" xlink:href="onco-20231231.xsd#onco_IncomeTaxesDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxContingencyLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxesPaidNetAbstract" xlink:to="IncomeTaxesDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxesDetailsTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLossMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLossMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_OperatingIncomeLossMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxesDetailsTable" xlink:to="us-gaap_IncomeTaxContingencyLineItems" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_DeferredFederalIncomeTaxExpenseBenefit" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredForeignIncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_DeferredForeignIncomeTaxExpenseBenefit" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_FederalStateAndLocalIncomeTaxExpenseBenefitContinuingOperations" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxContingencyLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/RetirementPlansDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAbstract"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="GrossPayPercentage" xlink:href="onco-20231231.xsd#onco_GrossPayPercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="GrossPayPercentage" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="DebtSecuritiesAndCash" xlink:href="onco-20231231.xsd#onco_DebtSecuritiesAndCash"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="DebtSecuritiesAndCash" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="EquitySecuritiesRate" xlink:href="onco-20231231.xsd#onco_EquitySecuritiesRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="EquitySecuritiesRate" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="AlternativeInvestmentsRate" xlink:href="onco-20231231.xsd#onco_AlternativeInvestmentsRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="AlternativeInvestmentsRate" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="RealEstateInvestmentsRate" xlink:href="onco-20231231.xsd#onco_RealEstateInvestmentsRate"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="RealEstateInvestmentsRate" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExcludingServiceCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExcludingServiceCostStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DefinedBenefitPlanAbstract" xlink:to="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExcludingServiceCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/SubsequentEventsDetails">
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventsAbstract"/>
    <loc xlink:type="locator" xlink:label="SubsequentEventsDetailsTable" xlink:href="onco-20231231.xsd#onco_SubsequentEventsDetailsTable"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventsAbstract" xlink:to="SubsequentEventsDetailsTable" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubsequentEventsDetailsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="ENTADFIMember" xlink:href="onco-20231231.xsd#onco_ENTADFIMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="ENTADFIMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubsequentEventsDetailsTable" xlink:to="us-gaap_DebtInstrumentAxis" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="NonConvertibleDebentureMember" xlink:href="onco-20231231.xsd#onco_NonConvertibleDebentureMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="NonConvertibleDebentureMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SubscriptionAgreementMember" xlink:href="onco-20231231.xsd#onco_SubscriptionAgreementMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="SubscriptionAgreementMember" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubsequentEventsDetailsTable" xlink:to="us-gaap_SubsequentEventTypeAxis" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SubsequentEventMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubsequentEventsDetailsTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="0.0"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SeriesAPreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_SeriesAPreferredStockMember" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="SubsequentEventsDetailsTable" xlink:to="us-gaap_SubsequentEventLineItems" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/label"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAnnualPrincipalPayment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAnnualPrincipalPayment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_DebtInstrumentAnnualPrincipalPayment" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage" order="1.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_InterestPayableCurrentAndNoncurrent" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="SeverancePayment" xlink:href="onco-20231231.xsd#onco_SeverancePayment"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="SeverancePayment" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventLineItems" xlink:to="us-gaap_OtherAssetImpairmentCharges" order="4.0" preferredLabel="http://www.xbrl.org/2009/role/netLabel"/>
  </presentationLink>
  <presentationLink xlink:type="extended" xlink:role="http://www.bluewatervaccines.com/role/DocumentAndEntityInformation">
    <loc xlink:type="locator" xlink:label="DocumentAndEntityInformationAbstract" xlink:href="onco-20231231.xsd#onco_DocumentAndEntityInformationAbstract"/>
    <loc xlink:type="locator" xlink:label="dei_DocumentInformationTable" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentInformationTable"/>
    <loc xlink:type="locator" xlink:label="dei_DocumentInformationLineItems" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentInformationLineItems"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DocumentAndEntityInformationAbstract" xlink:to="dei_DocumentInformationTable" order="1.0"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationTable" xlink:to="dei_DocumentInformationLineItems" order="1.0"/>
    <loc xlink:type="locator" xlink:label="dei_EntityRegistrantName" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityRegistrantName"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityRegistrantName" order="0.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_DocumentType" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentType"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_DocumentType" order="1.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_AmendmentFlag" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_AmendmentFlag"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AmendmentFlag" order="2.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_AmendmentDescription" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_AmendmentDescription"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_AmendmentDescription" order="3.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntityCentralIndexKey" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityCentralIndexKey"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityCentralIndexKey" order="4.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntityFilerCategory" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityFilerCategory"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityFilerCategory" order="5.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntitySmallBusiness" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntitySmallBusiness"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntitySmallBusiness" order="6.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityEmergingGrowthCompany"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityEmergingGrowthCompany" order="7.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntityExTransitionPeriod" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityExTransitionPeriod"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityExTransitionPeriod" order="8.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <loc xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityIncorporationStateCountryCode"/>
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems" xlink:to="dei_EntityIncorporationStateCountryCode" order="9.0" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </presentationLink>
</linkbase>
