<?xml version="1.0" encoding="UTF-8"?>
<!--XBRL Document Modified with Ez-Editor Version 1.0.2.9 on Monday, May 20, 2013 10:19:05 PM -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#CondensedBalanceSheets" roleURI="http://www.cellceutix.com/role/CondensedBalanceSheets"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#CondensedBalanceSheetsParentheticals" roleURI="http://www.cellceutix.com/role/CondensedBalanceSheetsParentheticals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StatementOfChangesInStockholdersDeficitUnaudited" roleURI="http://www.cellceutix.com/role/StatementOfChangesInStockholdersDeficitUnaudited"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StatementOfChangesInStockholdersDeficitUnauditedParentheticals" roleURI="http://www.cellceutix.com/role/StatementOfChangesInStockholdersDeficitUnauditedParentheticals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#BasisofPresentationandNatureofOperationsDetails" roleURI="http://www.cellceutix.com/role/BasisofPresentationandNatureofOperationsDetails"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#AccruedSalariesandPayrollTaxesRelatedPartiesDetails1" roleURI="http://www.cellceutix.com/role/AccruedSalariesandPayrollTaxesRelatedPartiesDetails1"/>



<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#GoingConcernDetailTextuals" roleURI="http://www.cellceutix.com/role/GoingConcernDetailTextuals"/>

<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#CommitmentsAndContingenciesDetailTextuals" roleURI="http://www.cellceutix.com/role/CommitmentsAndContingenciesDetailTextuals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#CommitmentsAndContingenciesDetailTextuals1" roleURI="http://www.cellceutix.com/role/CommitmentsAndContingenciesDetailTextuals1"/>

<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#RelatedPartyTransactionsDetailTextuals" roleURI="http://www.cellceutix.com/role/RelatedPartyTransactionsDetailTextuals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#RelatedPartyTransactionsDetailTextuals1" roleURI="http://www.cellceutix.com/role/RelatedPartyTransactionsDetailTextuals1"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#NotePayableRelatedPartyDetailTextuals" roleURI="http://www.cellceutix.com/role/NotePayableRelatedPartyDetailTextuals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#NotePayableRelatedPartyDetailTextuals1" roleURI="http://www.cellceutix.com/role/NotePayableRelatedPartyDetailTextuals1"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsStockOptionActivityDetails" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsStockOptionActivityDetails"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsOptionsOutstandingAndExercisableDetails1" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsOptionsOutstandingAndExercisableDetails1"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals1" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals1"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals2" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals2"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals3" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals3"/>
<roleRef xlink:type="simple" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals5" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals5"/>


<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#EquityTransactionsDetailTextuals4" roleURI="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals4"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#Equitytransactionsdetailtextuals" roleURI="http://www.cellceutix.com/role/Equitytransactionsdetailtextuals"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#EquityTransactionsDetailTextuals2" roleURI="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals2"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#EquityTransactionsDetailTextuals1" roleURI="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals1"/>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#EquityTransactionsDetailTextuals3" roleURI="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals3"/>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/CondensedBalanceSheets">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_StatementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3_Default" order="0" use="optional"/>


<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassAMember_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="loc_us-gaap_CommonClassBMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassBMember_6" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_AssetsAbstract_7" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_7" xlink:to="loc_us-gaap_AssetsCurrentAbstract_8" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Cash" xlink:label="loc_us-gaap_Cash_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8" xlink:to="loc_us-gaap_Cash_9" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_10" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_8" xlink:to="loc_us-gaap_AssetsCurrent_11" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssetsAbstract" xlink:label="loc_us-gaap_OtherAssetsAbstract_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_7" xlink:to="loc_us-gaap_OtherAssetsAbstract_12" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_12" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_13" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredOfferingCosts" xlink:label="loc_us-gaap_DeferredOfferingCosts_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_12" xlink:to="loc_us-gaap_DeferredOfferingCosts_14" order="10" use="optional"/>


<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_7" xlink:to="loc_us-gaap_Assets_16" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_18" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_AccountsPayableCurrent_19" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_20" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_21" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_22" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotesPayableRelatedPartiesClassifiedCurrent" xlink:label="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_23" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_24"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_18" xlink:to="loc_us-gaap_LiabilitiesCurrent_24" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_25"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_25" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesNoncurrent_26"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_25" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesNoncurrent_26" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_27"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_Liabilities_27" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_28"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_CommitmentsAndContingencies_28" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_29"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_StockholdersEquityAbstract_29" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_30"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_PreferredStockValue_30" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_31"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_CommonStockValue_31" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_32"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_AdditionalPaidInCapital_32" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage" xlink:label="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage_33"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage_33" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_34"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_TreasuryStockValue_34" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_35"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_29" xlink:to="loc_us-gaap_StockholdersEquity_35" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_36"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_17" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_36" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_12" xlink:to="loc_us-gaap_OtherAssets" order="20" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/CondensedBalanceSheetsParentheticals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_StatementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3_Default" order="0" use="optional"/>


<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassAMember_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="loc_us-gaap_CommonClassBMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassBMember_6" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_7" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrent_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_DueToRelatedPartiesCurrent_8" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_9" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_10" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_PreferredStockSharesIssued_11" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_12" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CommonStockVotesPerShare" xlink:label="loc_ctix_CommonStockVotesPerShare_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_ctix_CommonStockVotesPerShare_13" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_14" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_15" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_CommonStockSharesIssued_16" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_17" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockShares" xlink:label="loc_us-gaap_TreasuryStockShares_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_TreasuryStockShares_18" order="120" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StatementOfChangesInStockholdersDeficitUnaudited">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_StatementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2" xlink:to="loc_us-gaap_EquityComponentDomain_8" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_8_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2" xlink:to="loc_us-gaap_EquityComponentDomain_8_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8" xlink:to="loc_us-gaap_TreasuryStockMember_7" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedDeficitDuringDevelopmentStageMember" xlink:label="loc_us-gaap_AccumulatedDeficitDuringDevelopmentStageMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8" xlink:to="loc_us-gaap_AccumulatedDeficitDuringDevelopmentStageMember_6" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_5" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8" xlink:to="loc_us-gaap_PreferredStockMember_4" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8" xlink:to="loc_us-gaap_CommonStockMember_3" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreationDateAxis" xlink:label="loc_us-gaap_CreationDateAxis_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_CreationDateAxis_9" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DefaultFinancialStatementsDateMember" xlink:label="loc_us-gaap_DefaultFinancialStatementsDateMember_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreationDateAxis_9" xlink:to="loc_us-gaap_DefaultFinancialStatementsDateMember_21" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DefaultFinancialStatementsDateMember" xlink:label="loc_us-gaap_DefaultFinancialStatementsDateMember_21_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreationDateAxis_9" xlink:to="loc_us-gaap_DefaultFinancialStatementsDateMember_21_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_DecemberMember" xlink:label="loc_ctix_DecemberMember_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_DecemberMember_20" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NovemberMember" xlink:label="loc_ctix_NovemberMember_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_NovemberMember_19" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_OctoberMember" xlink:label="loc_ctix_OctoberMember_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_OctoberMember_18" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AugustMember" xlink:label="loc_ctix_AugustMember_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_AugustMember_17" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JulyMember" xlink:label="loc_ctix_JulyMember_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_JulyMember_16" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JuneMember" xlink:label="loc_ctix_JuneMember_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_JuneMember_15" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MayMember" xlink:label="loc_ctix_MayMember_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_MayMember_14" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AprilMember" xlink:label="loc_ctix_AprilMember_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_AprilMember_13" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MarchMember" xlink:label="loc_ctix_MarchMember_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_MarchMember_12" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_FebruaryMember" xlink:label="loc_ctix_FebruaryMember_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_FebruaryMember_11" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JanuaryMember" xlink:label="loc_ctix_JanuaryMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_21" xlink:to="loc_ctix_JanuaryMember_10" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockholdersEquity_23" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaap_SharesOutstanding_24"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_SharesOutstanding_24" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueExchangeOfOwnersEquity" xlink:label="loc_ctix_StockIssuedDuringPeriodValueExchangeOfOwnersEquity_25"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueExchangeOfOwnersEquity_25" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesExchangeOfOwnersEquity" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesExchangeOfOwnersEquity_26"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesExchangeOfOwnersEquity_26" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueMerger" xlink:label="loc_ctix_StockIssuedDuringPeriodValueMerger_27"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueMerger_27" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesMerger" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesMerger_28"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesMerger_28" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_29"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_29" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_30"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_30" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueIssuedForCancellation" xlink:label="loc_ctix_StockIssuedDuringPeriodValueIssuedForCancellation_31"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueIssuedForCancellation_31" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodShareIssuedForCancellation" xlink:label="loc_ctix_StockIssuedDuringPeriodShareIssuedForCancellation_32"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodShareIssuedForCancellation_32" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfDebt" xlink:label="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfDebt_33"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfDebt_33" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_34"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_34" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_35"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_35" order="120" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CapitalContributed" xlink:label="loc_ctix_CapitalContributed_36"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_CapitalContributed_36" order="130" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CancellationOfPreviouslyIssuedCommonStockValue" xlink:label="loc_ctix_CancellationOfPreviouslyIssuedCommonStockValue_37"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_CancellationOfPreviouslyIssuedCommonStockValue_37" order="140" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CancellationOfPreviouslyIssuedCommonStockShares" xlink:label="loc_ctix_CancellationOfPreviouslyIssuedCommonStockShares_38"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_CancellationOfPreviouslyIssuedCommonStockShares_38" order="150" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AdjustmentsToAdditionalPaidInCapitalModificationOfStockOptions" xlink:label="loc_ctix_AdjustmentsToAdditionalPaidInCapitalModificationOfStockOptions_39"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_AdjustmentsToAdditionalPaidInCapitalModificationOfStockOptions_39" order="160" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability" xlink:label="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability_40"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability_40" order="170" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_RepurchaseOfCommonStockValue" xlink:label="loc_ctix_RepurchaseOfCommonStockValue_41"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_RepurchaseOfCommonStockValue_41" order="180" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_RepurchaseOfCommonStockShares" xlink:label="loc_ctix_RepurchaseOfCommonStockShares_42"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_RepurchaseOfCommonStockShares_42" order="190" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition_43"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationStockOptionsRequisiteServicePeriodRecognition_43" order="200" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueCharitableContributions" xlink:label="loc_ctix_StockIssuedDuringPeriodValueCharitableContributions_44"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueCharitableContributions_44" order="210" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesCharitableContributions" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesCharitableContributions_45"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesCharitableContributions_45" order="220" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_46"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_46" order="230" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_47"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_47" order="240" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueIssuedForServicesTwo" xlink:label="loc_ctix_StockIssuedDuringPeriodValueIssuedForServicesTwo_48"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueIssuedForServicesTwo_48" order="250" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodShareIssuedForServicesTwo" xlink:label="loc_ctix_StockIssuedDuringPeriodShareIssuedForServicesTwo_49"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodShareIssuedForServicesTwo_49" order="260" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueCommitmentFee" xlink:label="loc_ctix_StockIssuedDuringPeriodValueCommitmentFee_50"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueCommitmentFee_50" order="270" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesCommitmentFee" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesCommitmentFee_51"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesCommitmentFee_51" order="280" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForCash" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForCash_52"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForCash_52" order="290" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForCash" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForCash_53"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForCash_53" order="300" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_54"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_54" order="310" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_55"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_55" order="320" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueWarrantsExercised" xlink:label="loc_ctix_StockIssuedDuringPeriodValueWarrantsExercised_56"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueWarrantsExercised_56" order="330" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesWarrantsExercised" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesWarrantsExercised_57"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesWarrantsExercised_57" order="340" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_58"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_58" order="350" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_59"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_59" order="360" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ReclassificationOfWarrantLiabilitiesToEquity" xlink:label="loc_ctix_ReclassificationOfWarrantLiabilitiesToEquity_60"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_ReclassificationOfWarrantLiabilitiesToEquity_60" order="370" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockRetiredCostMethodAmount" xlink:label="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_61"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_61" order="380" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockSharesRetired" xlink:label="loc_us-gaap_TreasuryStockSharesRetired_62"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_TreasuryStockSharesRetired_62" order="390" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValuePreferredStock" xlink:label="loc_ctix_StockIssuedDuringPeriodValuePreferredStock_63"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValuePreferredStock_63" order="400" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesPreferredStock" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesPreferredStock_64"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesPreferredStock_64" order="410" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_65"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_65" order="420" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodValueConversionOfPreferredStockToCommonStock" xlink:label="loc_ctix_StockIssuedDuringPeriodValueConversionOfPreferredStockToCommonStock_66"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodValueConversionOfPreferredStockToCommonStock_66" order="430" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesConversionOfPreferredStockToCommonStock" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesConversionOfPreferredStockToCommonStock_67"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesConversionOfPreferredStockToCommonStock_67" order="440" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_68"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_22" xlink:to="loc_us-gaap_NetIncomeLoss_68" order="450" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StatementOfChangesInStockholdersDeficitUnauditedParentheticals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_StatementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreationDateAxis" xlink:label="loc_us-gaap_CreationDateAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_CreationDateAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DefaultFinancialStatementsDateMember" xlink:label="loc_us-gaap_DefaultFinancialStatementsDateMember_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreationDateAxis_2" xlink:to="loc_us-gaap_DefaultFinancialStatementsDateMember_14" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DefaultFinancialStatementsDateMember" xlink:label="loc_us-gaap_DefaultFinancialStatementsDateMember_14_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreationDateAxis_2" xlink:to="loc_us-gaap_DefaultFinancialStatementsDateMember_14_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_DecemberMember" xlink:label="loc_ctix_DecemberMember_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_DecemberMember_13" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NovemberMember" xlink:label="loc_ctix_NovemberMember_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_NovemberMember_12" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_OctoberMember" xlink:label="loc_ctix_OctoberMember_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_OctoberMember_11" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AugustMember" xlink:label="loc_ctix_AugustMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_AugustMember_10" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JulyMember" xlink:label="loc_ctix_JulyMember_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_JulyMember_9" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JuneMember" xlink:label="loc_ctix_JuneMember_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_JuneMember_8" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MayMember" xlink:label="loc_ctix_MayMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_MayMember_7" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AprilMember" xlink:label="loc_ctix_AprilMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_AprilMember_6" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MarchMember" xlink:label="loc_ctix_MarchMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_MarchMember_5" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_FebruaryMember" xlink:label="loc_ctix_FebruaryMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_FebruaryMember_4" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_JanuaryMember" xlink:label="loc_ctix_JanuaryMember_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefaultFinancialStatementsDateMember_14" xlink:to="loc_ctix_JanuaryMember_3" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1" xlink:to="loc_us-gaap_RangeAxis_15" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_15" xlink:to="loc_us-gaap_RangeMember_16" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_16_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_15" xlink:to="loc_us-gaap_RangeMember_16_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_16" xlink:to="loc_us-gaap_MaximumMember_17" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_16" xlink:to="loc_us-gaap_MinimumMember_18" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityIssuancePerShareAmount" xlink:label="loc_us-gaap_EquityIssuancePerShareAmount_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_us-gaap_EquityIssuancePerShareAmount_19" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIssuancePerShareAmountTwo" xlink:label="loc_ctix_EquityIssuancePerShareAmountTwo_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_ctix_EquityIssuancePerShareAmountTwo_20" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIssuancePerShareAmountCharitableContributions" xlink:label="loc_ctix_EquityIssuancePerShareAmountCharitableContributions_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_ctix_EquityIssuancePerShareAmountCharitableContributions_21" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIssuancePerShareAmountCommitmentFee" xlink:label="loc_ctix_EquityIssuancePerShareAmountCommitmentFee_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_ctix_EquityIssuancePerShareAmountCommitmentFee_22" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIssuancePerShareAmountNetOfOfferingCosts" xlink:label="loc_ctix_EquityIssuancePerShareAmountNetOfOfferingCosts_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_0" xlink:to="loc_ctix_EquityIssuancePerShareAmountNetOfOfferingCosts_23" order="50" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/BasisofPresentationandNatureofOperationsDetails">
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_BusinessDescriptionAndBasisOfPresentationLineItems" xlink:label="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_BusinessDescriptionAndBasisOfPresentationTable" xlink:label="loc_ctix_BusinessDescriptionAndBasisOfPresentationTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0" xlink:to="loc_ctix_BusinessDescriptionAndBasisOfPresentationTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationTable_1" xlink:to="loc_us-gaap_StatementGeographicalAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CountriesWhereCompositionOfMatterPatentsIssuedMember" xlink:label="loc_ctix_CountriesWhereCompositionOfMatterPatentsIssuedMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_ctix_CountriesWhereCompositionOfMatterPatentsIssuedMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_OtherCountriesMember" xlink:label="loc_ctix_OtherCountriesMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_ctix_OtherCountriesMember_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfPharmaceuticalCompounds" xlink:label="loc_ctix_NumberOfPharmaceuticalCompounds_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0" xlink:to="loc_ctix_NumberOfPharmaceuticalCompounds_6" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfCompoundsForWhichPatentApplicationsFiled" xlink:label="loc_ctix_NumberOfCompoundsForWhichPatentApplicationsFiled_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0" xlink:to="loc_ctix_NumberOfCompoundsForWhichPatentApplicationsFiled_7" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfNetSalesAgreedToPayToInvestor" xlink:label="loc_ctix_PercentageOfNetSalesAgreedToPayToInvestor_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0" xlink:to="loc_ctix_PercentageOfNetSalesAgreedToPayToInvestor_8" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AmountPaidToInvestors" xlink:label="loc_ctix_AmountPaidToInvestors_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_BusinessDescriptionAndBasisOfPresentationLineItems_0" xlink:to="loc_ctix_AmountPaidToInvestors_9" order="40" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/AccruedSalariesandPayrollTaxesRelatedPartiesDetails1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ChiefExecutiveOfficerMember" xlink:label="loc_us-gaap_ChiefExecutiveOfficerMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3" xlink:to="loc_us-gaap_ChiefExecutiveOfficerMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ChiefScientificOfficerMember" xlink:label="loc_ctix_ChiefScientificOfficerMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3" xlink:to="loc_ctix_ChiefScientificOfficerMember_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfExecutiveOfficers" xlink:label="loc_ctix_NumberOfExecutiveOfficers_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_ctix_NumberOfExecutiveOfficers_6" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OfficersCompensation" xlink:label="loc_us-gaap_OfficersCompensation_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_OfficersCompensation_7" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfAnnualIncreaseInSalary" xlink:label="loc_ctix_PercentageOfAnnualIncreaseInSalary_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_ctix_PercentageOfAnnualIncreaseInSalary_8" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PeriodOfAgreement" xlink:label="loc_ctix_PeriodOfAgreement"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_ctix_PeriodOfAgreement" order="40" use="optional"/>
</definitionLink>



<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/GoingConcernDetailTextuals">
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementLineItems" xlink:label="loc_ctix_AgreementLineItems_0"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementTable" xlink:label="loc_ctix_AgreementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_AgreementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementAxis" xlink:label="loc_ctix_AgreementAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_ctix_AgreementAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_FinancingAgreementMember" xlink:label="loc_ctix_FinancingAgreementMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementDomain_3" xlink:to="loc_ctix_FinancingAgreementMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_dei_LegalEntityAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5" xlink:to="loc_dei_EntityDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5" xlink:to="loc_dei_EntityDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AspireCapitalFundLlcMember" xlink:label="loc_ctix_AspireCapitalFundLlcMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6" xlink:to="loc_ctix_AspireCapitalFundLlcMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WorkingCapitalRequirementFundsObtainedFromFinancingAgreement" xlink:label="loc_ctix_WorkingCapitalRequirementFundsObtainedFromFinancingAgreement_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_WorkingCapitalRequirementFundsObtainedFromFinancingAgreement_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage" xlink:label="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WorkingCapitalDeficit" xlink:label="loc_ctix_WorkingCapitalDeficit"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_WorkingCapitalDeficit" order="40" use="optional"/>
</definitionLink>

<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/CommitmentsAndContingenciesDetailTextuals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementTable" xlink:label="loc_ctix_AgreementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_ctix_AgreementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementAxis" xlink:label="loc_ctix_AgreementAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_ctix_AgreementAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_SettlementAgreementMember" xlink:label="loc_ctix_SettlementAgreementMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementDomain_3" xlink:to="loc_ctix_SettlementAgreementMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_FormerCeoMember" xlink:label="loc_ctix_FormerCeoMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6" xlink:to="loc_ctix_FormerCeoMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PeriodForRepurchaseOfShares" xlink:label="loc_ctix_PeriodForRepurchaseOfShares_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_ctix_PeriodForRepurchaseOfShares_9" order="20" use="optional"/>


<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaap_RepaymentsOfRelatedPartyDebt_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_us-gaap_RepaymentsOfRelatedPartyDebt_11" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockSharesRetired" xlink:label="loc_us-gaap_TreasuryStockSharesRetired_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_us-gaap_TreasuryStockSharesRetired_12" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockShares" xlink:label="loc_us-gaap_TreasuryStockShares_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_us-gaap_TreasuryStockShares_13" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability" xlink:label="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_ctix_AdjustmentsToAdditionalPaidInCapitalForgivenessOfLiability_14" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_SettlementLiability" xlink:label="loc_ctix_SettlementLiability_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_ctix_SettlementLiability_15" order="80" use="optional"/>


<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_0" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue" order="100" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/CommitmentsAndContingenciesDetailTextuals1">
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementLineItems" xlink:label="loc_ctix_AgreementLineItems_0"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementTable" xlink:label="loc_ctix_AgreementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_AgreementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementAxis" xlink:label="loc_ctix_AgreementAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_ctix_AgreementAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_LegalSettlementAgreementMember" xlink:label="loc_ctix_LegalSettlementAgreementMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementDomain_3" xlink:to="loc_ctix_LegalSettlementAgreementMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_dei_LegalEntityAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5" xlink:to="loc_dei_EntityDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5" xlink:to="loc_dei_EntityDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ToxikonCorporationMember" xlink:label="loc_ctix_ToxikonCorporationMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6" xlink:to="loc_ctix_ToxikonCorporationMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_8" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_8" xlink:to="loc_us-gaap_ClassOfStockDomain_9" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_9_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_8" xlink:to="loc_us-gaap_ClassOfStockDomain_9_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_9" xlink:to="loc_us-gaap_CommonClassAMember_10" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsForLegalSettlements" xlink:label="loc_us-gaap_PaymentsForLegalSettlements_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_PaymentsForLegalSettlements_11" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_12" order="20" use="optional"/>


</definitionLink>

<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/RelatedPartyTransactionsDetailTextuals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_KardScientificMember" xlink:label="loc_ctix_KardScientificMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3" xlink:to="loc_ctix_KardScientificMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_OperatingLeasesRentExpenseMonthlyRent" xlink:label="loc_ctix_OperatingLeasesRentExpenseMonthlyRent_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_ctix_OperatingLeasesRentExpenseMonthlyRent_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedRentNoncurrent" xlink:label="loc_us-gaap_AccruedRentNoncurrent_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_AccruedRentNoncurrent_6" order="20" use="optional"/>


</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/RelatedPartyTransactionsDetailTextuals1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2" xlink:to="loc_us-gaap_RelatedPartyDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_KardScientificMember" xlink:label="loc_ctix_KardScientificMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3" xlink:to="loc_ctix_KardScientificMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_6" order="20" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/NotePayableRelatedPartyDetailTextuals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_DebtInstrumentTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConvertibleNotesPayableMember" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OfficerMember" xlink:label="loc_us-gaap_OfficerMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6" xlink:to="loc_us-gaap_OfficerMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1" xlink:to="loc_us-gaap_DebtInstrumentAxis_8" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PromissoryNotePayableMember" xlink:label="loc_ctix_PromissoryNotePayableMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9" xlink:to="loc_ctix_PromissoryNotePayableMember_10" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PromissoryNotePayableBMember" xlink:label="loc_ctix_PromissoryNotePayableBMember_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9" xlink:to="loc_ctix_PromissoryNotePayableBMember_11" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PromissoryNotePayableCMember" xlink:label="loc_ctix_PromissoryNotePayableCMember_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9" xlink:to="loc_ctix_PromissoryNotePayableCMember_12" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentIncreaseAdditionalBorrowings" xlink:label="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_13" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_14" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_15" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfInterestRateChange" xlink:label="loc_ctix_PercentageOfInterestRateChange_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_PercentageOfInterestRateChange_16" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_DebtInstrumentAccruedInterestConvertedIntoAdditionalPrincipal" xlink:label="loc_ctix_DebtInstrumentAccruedInterestConvertedIntoAdditionalPrincipal_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_DebtInstrumentAccruedInterestConvertedIntoAdditionalPrincipal_17" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotesPayableRelatedPartiesClassifiedCurrent" xlink:label="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_18" order="60" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/NotePayableRelatedPartyDetailTextuals1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_DebtInstrumentTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PromissoryNotePayableCMember" xlink:label="loc_ctix_PromissoryNotePayableCMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3" xlink:to="loc_ctix_PromissoryNotePayableCMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OfficerMember" xlink:label="loc_us-gaap_OfficerMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6" xlink:to="loc_us-gaap_OfficerMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesAgainstOfficerLoan" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesAgainstOfficerLoan_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesAgainstOfficerLoan_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ClosingBidPriceOfShares" xlink:label="loc_ctix_ClosingBidPriceOfShares_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_ClosingBidPriceOfShares_9" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MaximumPercentageOfClosingBidPriceOnDateFactor" xlink:label="loc_ctix_MaximumPercentageOfClosingBidPriceOnDateFactor_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_MaximumPercentageOfClosingBidPriceOnDateFactor_10" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_VestingTermOfShares" xlink:label="loc_ctix_VestingTermOfShares_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_ctix_VestingTermOfShares_11" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestReceivable" xlink:label="loc_us-gaap_InterestReceivable_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_InterestReceivable_12" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotesPayableRelatedPartiesClassifiedCurrent" xlink:label="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_0" xlink:to="loc_us-gaap_NotesPayableRelatedPartiesClassifiedCurrent_13" order="60" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsStockOptionActivityDetails">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" xlink:to="loc_us-gaap_StockOptionsMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_RangeAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_5" xlink:to="loc_us-gaap_RangeMember_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_5" xlink:to="loc_us-gaap_RangeMember_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_6" xlink:to="loc_us-gaap_MaximumMember_7" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_6" xlink:to="loc_us-gaap_MinimumMember_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_9" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_10" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_11" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_12" order="40" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsOptionsOutstandingAndExercisableDetails1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" xlink:to="loc_us-gaap_StockOptionsMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_7" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_9" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_10" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_12" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_13" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_14" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_15" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_11" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_16" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward" xlink:label="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_18" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedWeightedAverageRemainingContractualTerm" xlink:label="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedWeightedAverageRemainingContractualTerm_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17" xlink:to="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedWeightedAverageRemainingContractualTerm_19" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermThree" xlink:label="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermThree_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17" xlink:to="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermThree_20" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTermRollForward_17" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_21" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_22" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_23" order="50" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" xlink:to="loc_us-gaap_StockOptionsMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ConsultantsMember" xlink:label="loc_ctix_ConsultantsMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6" xlink:to="loc_ctix_ConsultantsMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CompensationExpensesPerMonth" xlink:label="loc_ctix_CompensationExpensesPerMonth_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_CompensationExpensesPerMonth_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_9" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_IncreaseInCompensationExpensesPerMonth" xlink:label="loc_ctix_IncreaseInCompensationExpensesPerMonth_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_IncreaseInCompensationExpensesPerMonth_10" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfStockOptionsAwardedToConsultant" xlink:label="loc_ctix_NumberOfStockOptionsAwardedToConsultant_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_NumberOfStockOptionsAwardedToConsultant_11" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross_12" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_13" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProfessionalFees" xlink:label="loc_us-gaap_ProfessionalFees_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ProfessionalFees_14" order="70" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_PlanNameAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_IncentiveStockOptionsPlan2009Member" xlink:label="loc_ctix_IncentiveStockOptionsPlan2009Member_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3" xlink:to="loc_ctix_IncentiveStockOptionsPlan2009Member_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_5" order="10" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals2">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_PlanNameAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIncentivePlan2010Member" xlink:label="loc_ctix_EquityIncentivePlan2010Member_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3" xlink:to="loc_ctix_EquityIncentivePlan2010Member_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_TermOfIncentiveStockOptionGranted" xlink:label="loc_ctix_TermOfIncentiveStockOptionGranted_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_TermOfIncentiveStockOptionGranted_6" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfCombinedVotingPower" xlink:label="loc_ctix_PercentageOfCombinedVotingPower_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_PercentageOfCombinedVotingPower_7" order="30" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals3">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3" xlink:to="loc_us-gaap_StockOptionsMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_6" order="20" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals5">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_1" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_2" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_2" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaap_WarrantMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_3" xlink:to="loc_us-gaap_WarrantMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WarrantsIssuedAndOutstanding" xlink:label="loc_ctix_WarrantsIssuedAndOutstanding_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_ctix_WarrantsIssuedAndOutstanding_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WeightedAverageExercisePriceOfWarrants" xlink:label="loc_ctix_WeightedAverageExercisePriceOfWarrants_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_ctix_WeightedAverageExercisePriceOfWarrants_6" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WarrantsExpired" xlink:label="loc_ctix_WarrantsExpired_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_ctix_WarrantsExpired_7" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WarrantsOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_ctix_WarrantsOptionsOutstandingWeightedAverageRemainingContractualTerm2_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_ctix_WarrantsOptionsOutstandingWeightedAverageRemainingContractualTerm2_8" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_WarrantsOptionsOutstandingIntrinsicValue" xlink:label="loc_ctix_WarrantsOptionsOutstandingIntrinsicValue_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_0" xlink:to="loc_ctix_WarrantsOptionsOutstandingIntrinsicValue_9" order="50" use="optional"/>
</definitionLink>


<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals4">
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementLineItems" xlink:label="loc_ctix_AgreementLineItems_0"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementTable" xlink:label="loc_ctix_AgreementTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_AgreementTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementAxis" xlink:label="loc_ctix_AgreementAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_ctix_AgreementAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AgreementDomain" xlink:label="loc_ctix_AgreementDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ctix_AgreementAxis_2" xlink:to="loc_ctix_AgreementDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CommonStockPurchaseAgreementMember" xlink:label="loc_ctix_CommonStockPurchaseAgreementMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementDomain_3" xlink:to="loc_ctix_CommonStockPurchaseAgreementMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5" xlink:to="loc_us-gaap_ClassOfStockDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5" xlink:to="loc_us-gaap_ClassOfStockDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_6" xlink:to="loc_us-gaap_CommonClassAMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ctix_AgreementTable_1" xlink:to="loc_dei_LegalEntityAxis_8" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8" xlink:to="loc_dei_EntityDomain_9" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_9_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8" xlink:to="loc_dei_EntityDomain_9_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AspireCapitalFundLlcMember" xlink:label="loc_ctix_AspireCapitalFundLlcMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_9" xlink:to="loc_ctix_AspireCapitalFundLlcMember_10" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CommonStockSharesCommittedToPurchaseValue" xlink:label="loc_ctix_CommonStockSharesCommittedToPurchaseValue_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_CommonStockSharesCommittedToPurchaseValue_11" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_TermOfAgreement" xlink:label="loc_ctix_TermOfAgreement_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_TermOfAgreement_12" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_StockIssuedDuringPeriodSharesCommitmentFee" xlink:label="loc_ctix_StockIssuedDuringPeriodSharesCommitmentFee_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_StockIssuedDuringPeriodSharesCommitmentFee_13" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForCash" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForCash_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForCash_14" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForCash" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForCash_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForCash_15" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfSharesAuthorizedToPurchasedPerBusinessDay" xlink:label="loc_ctix_NumberOfSharesAuthorizedToPurchasedPerBusinessDay_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_NumberOfSharesAuthorizedToPurchasedPerBusinessDay_16" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AmountOfSharesAuthorizedToPurchasedPerBusinessDay" xlink:label="loc_ctix_AmountOfSharesAuthorizedToPurchasedPerBusinessDay_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_AmountOfSharesAuthorizedToPurchasedPerBusinessDay_17" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PeriodOfPriorWrittenNotice" xlink:label="loc_ctix_PeriodOfPriorWrittenNotice_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_PeriodOfPriorWrittenNotice_18" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfTradingVolumesForNextBusinessDays" xlink:label="loc_ctix_PercentageOfTradingVolumesForNextBusinessDays_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_PercentageOfTradingVolumesForNextBusinessDays_19" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_VolumeWeightedAveragePricePurchasePriceDescription" xlink:label="loc_ctix_VolumeWeightedAveragePricePurchasePriceDescription_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_VolumeWeightedAveragePricePurchasePriceDescription_20" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ThresholdLimitOfVolumeWeightedAveragePricePurchasePrice" xlink:label="loc_ctix_ThresholdLimitOfVolumeWeightedAveragePricePurchasePrice_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_ctix_ThresholdLimitOfVolumeWeightedAveragePricePurchasePrice_21" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_22" order="120" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ctix_AgreementLineItems_0" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_23" order="130" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/Equitytransactionsdetailtextuals">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SeriesAPreferredStockMember" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassAMember_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_PreferredStockMember_6" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonStockMember_7" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_8" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_9" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_9_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_8" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_9_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WarrantMember" xlink:label="loc_us-gaap_WarrantMember_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_9" xlink:to="loc_us-gaap_WarrantMember_10" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AmountGrantedUnderSubscriptionAgreement" xlink:label="loc_ctix_AmountGrantedUnderSubscriptionAgreement_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_AmountGrantedUnderSubscriptionAgreement_11" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_12" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_13" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_InstallmentFundingTerm" xlink:label="loc_ctix_InstallmentFundingTerm_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_InstallmentFundingTerm_14" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageOfTotalVolumeTradedFactorTwo" xlink:label="loc_ctix_PercentageOfTotalVolumeTradedFactorTwo_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_PercentageOfTotalVolumeTradedFactorTwo_15" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_NumberOfTradingDaysFactorTwo" xlink:label="loc_ctix_NumberOfTradingDaysFactorTwo_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_NumberOfTradingDaysFactorTwo_16" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_MaximumPercentageOfClosingBidPriceOnDateFactorTwo" xlink:label="loc_ctix_MaximumPercentageOfClosingBidPriceOnDateFactorTwo_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_MaximumPercentageOfClosingBidPriceOnDateFactorTwo_17" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_LowestBidPricePercentagePriorToConversionFactorTwo" xlink:label="loc_ctix_LowestBidPricePercentagePriorToConversionFactorTwo_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_LowestBidPricePercentagePriorToConversionFactorTwo_18" order="80" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_LowestBidPriceNumberOfDaysPriorToConversionFactorTwo" xlink:label="loc_ctix_LowestBidPriceNumberOfDaysPriorToConversionFactorTwo_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_LowestBidPriceNumberOfDaysPriorToConversionFactorTwo_19" order="90" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PercentageCommonStockOwnedOfTotalCommonStockOutstanding" xlink:label="loc_ctix_PercentageCommonStockOwnedOfTotalCommonStockOutstanding_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_PercentageCommonStockOwnedOfTotalCommonStockOutstanding_20" order="100" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ExpiryTermOfWarrants" xlink:label="loc_ctix_ExpiryTermOfWarrants_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_ExpiryTermOfWarrants_21" order="110" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_22" order="120" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_PreferredStockConversionPrice" xlink:label="loc_ctix_PreferredStockConversionPrice_23"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_PreferredStockConversionPrice_23" order="130" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SaleOfStockPricePerShare" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_24"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_24" order="140" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AggregateAmountFundedUnderSubscriptionAgreement" xlink:label="loc_ctix_AggregateAmountFundedUnderSubscriptionAgreement_25"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_AggregateAmountFundedUnderSubscriptionAgreement_25" order="150" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_26"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_26" order="160" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_27"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights_27" order="170" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_TerminationOfSubscriptionForRemainingAmountOfSubscriptionAgreement" xlink:label="loc_ctix_TerminationOfSubscriptionForRemainingAmountOfSubscriptionAgreement_28"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_ctix_TerminationOfSubscriptionForRemainingAmountOfSubscriptionAgreement_28" order="180" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals2">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassAMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5" xlink:to="loc_us-gaap_RelatedPartyDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ConsultantsMember" xlink:label="loc_ctix_ConsultantsMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6" xlink:to="loc_ctix_ConsultantsMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_9" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_SharePrice_10" order="30" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals1">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2" xlink:to="loc_us-gaap_ClassOfStockDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3" xlink:to="loc_us-gaap_CommonClassAMember_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6" xlink:to="loc_us-gaap_StockOptionsMember_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_9" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_10" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_11" order="40" use="optional"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/EquityTransactionsDetailTextuals3">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_PlanNameAxis_2" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_3_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_2" xlink:to="loc_us-gaap_PlanNameDomain_3_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIncentivePlans2009And2010Member" xlink:label="loc_ctix_EquityIncentivePlans2009And2010Member_4"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3" xlink:to="loc_ctix_EquityIncentivePlans2009And2010Member_4" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_EquityIncentivePlans2010Member" xlink:label="loc_ctix_EquityIncentivePlans2010Member_5"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3" xlink:to="loc_ctix_EquityIncentivePlans2010Member_5" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_6"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_6" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_7"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_6" xlink:to="loc_us-gaap_ClassOfStockDomain_7" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_7_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_6" xlink:to="loc_us-gaap_ClassOfStockDomain_7_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_8"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_7" xlink:to="loc_us-gaap_CommonClassAMember_8" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_9"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_AwardTypeAxis_9" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_11"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10" xlink:to="loc_us-gaap_StockOptionsMember_11" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_12"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_12" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_13"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_12" xlink:to="loc_us-gaap_RelatedPartyDomain_13" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_13_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_12" xlink:to="loc_us-gaap_RelatedPartyDomain_13_Default" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_ConsultantsMember" xlink:label="loc_ctix_ConsultantsMember_14"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_13" xlink:to="loc_ctix_ConsultantsMember_14" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_15"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_15" order="10" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_16"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_16" order="20" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_SharesIssuedForServicesAtEndOfEachMonth" xlink:label="loc_ctix_SharesIssuedForServicesAtEndOfEachMonth_17"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_SharesIssuedForServicesAtEndOfEachMonth_17" order="30" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_18"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_18" order="40" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AggregateNumberOfOptionsAwardedDuringPeriod" xlink:label="loc_ctix_AggregateNumberOfOptionsAwardedDuringPeriod_19"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_ctix_AggregateNumberOfOptionsAwardedDuringPeriod_19" order="50" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_20"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_20" order="60" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_21"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_21" order="70" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_22"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_22" order="80" use="optional"/>
</definitionLink>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#StockOptionsAndWarrantsDetailTextuals4" roleURI="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals4"/>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/StockOptionsAndWarrantsDetailTextuals4"><loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems"/>






<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable" order="10" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>








<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable" xlink:to="loc_us-gaap_StatementClassOfStockAxis" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis" xlink:to="loc_us-gaap_ClassOfStockDomain" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain" xlink:to="loc_us-gaap_CommonClassAMember" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_Default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis" xlink:to="loc_us-gaap_ClassOfStockDomain_Default" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaap_CommonStockSharesIssued" order="11" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare" order="12" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_CommonStockPurchaseWarrantExercisablePrice" xlink:label="loc_ctix_CommonStockPurchaseWarrantExercisablePrice"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="loc_ctix_CommonStockPurchaseWarrantExercisablePrice" order="13" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfWarrants" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants" order="14" use="optional"/>
</definitionLink>
<roleRef xlink:type="simple" xlink:href="ctix-20130331.xsd#SubsequentEventsDetailTextuals" roleURI="http://www.cellceutix.com/role/SubsequentEventsDetailTextuals"/>
<definitionLink xlink:type="extended" xlink:role="http://www.cellceutix.com/role/SubsequentEventsDetailTextuals">


































<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="loc_us-gaap_SubsequentEventTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_1" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_1" xlink:to="loc_us-gaap_SubsequentEventMember_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_1_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_1_2" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_1" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_1" xlink:to="loc_us-gaap_ClassOfStockDomain_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_1" xlink:to="loc_us-gaap_CommonClassAMember_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_1_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_1" xlink:to="loc_us-gaap_ClassOfStockDomain_1_2" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_1" xlink:to="loc_dei_LegalEntityAxis_1" order="2" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_1" xlink:to="loc_dei_EntityDomain_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="ctix-20130331.xsd#ctix_AspireCapitalFundLlcMember" xlink:label="loc_ctix_AspireCapitalFundLlcMember_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_1" xlink:to="loc_ctix_AspireCapitalFundLlcMember_1" order="0" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_1_2"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_1" xlink:to="loc_dei_EntityDomain_1_2" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_1" order="1" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_1" order="2" use="optional"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_1"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_1" order="3" use="optional"/>
</definitionLink>
</linkbase>


