AIM:ToexploreexpressionsofPIK3CAintheprogressionofgastriccancerfromprimarytometastasisanditseffectsonactivationofphosphatidylinositol3-kinase(PI3K)/Aktpathway.METHODS:mRNAandproteinlevelsofPIK3CAwereassessed,respectively,byreal-timequantitativepolymerasechainreactionandimmunohistochemistryinspecimensofnormalgastricmucosa,primaryfociandlymphnodeanddistantmetastasisofgastriccancer.AktandphosphorylatedAktproteinwerealsoexaminedbyWesternblottinginthesetissues,inordertoanalyzetheeffectofPIK3CAexpressionlevelchangesontheactivationofPI3K/Aktsignalingpathway.RESULTS:PIK3CAmRNAinlymphnodemetastasiswereapproximately5and2foldshigher,respectively,thanthatinthecorrespondingnormalgastricmucosaandprimarygastriccancertissues(P<0.05),whilenostatisticalsignificancewasfoundcomparedwithdistantmetastasis.Immunohistochemically,PIK3CAproteinexpressionwasdiscoveredin7(35%)specimensof20primaryfocivs10(67%)of15oflymphnodemetastasisor11(61%)of18ofdistantmetastasis(35%vs67%,P=0.015;35%vs61%,P=0.044).WiththeincreasedlevelofPIK3CAexpression,thetotalAktproteinexpressionremainedalmostunchanged,butp-Aktproteinwasupregulatedmarkedly.CONCLUSION:IncreasedexpressionofPIK3CAisexpectedtobeapromisingindicatorofmetastasisingastriccancer.Up-regulationofPIK3CAmaypromotethemetastasisofgastriccancerthroughaberrantactivationofPI3K/Aktsignaling.
