简介：AIM:Toanalyzethemismatchrepair(MMR)statusandtheARID1Aexpressionaswellastheirclinicopathologicalsignificanceingastricadenocarcinomas.METHODS:WeexaminedtheexpressionsofMMRproteinsandARID1Abyimmunohistochemistryinconsecutive489primarygastricadenocarcinomas.Theresultswerefurthercorrelatedwithclinicopathologicalvariables.RESULTS:ThelossofanyMMRproteinexpression,indicativeofMMRdeficiency,wasobservedin38cases(7.8%)andwassignificantlyassociatedwithanolderage(68.6±9.2vs60.4±11.7,P<0.001),afemalesex(55.3%vs31.3%,P=0.004),anantrallocation(44.7%vs25.7%,P=0.021),andadifferentiatedhistology(57.9%vs39.7%,P=0.023).AbnormalARID1Aexpression,includingreducedorlossofARID1Aexpression,wasobservedin109cases(22.3%)andwassignificantlycorrelatedwithlymphaticinvasion(80.7%vs69.5%,P=0.022)andlymphnodemetastasis(83.5%vs73.7%,P=0.042).ThetumorswithabnormalARID1AexpressionmorefrequentlyindicatedMMRdeficiency(47.4%vs20.2%,P<0.001).AmultivariateanalysisidentifiedabnormalARID1Aexpressionasanindependentpoorprognosticfactor(HR=1.36,95%CI:1.01-1.84;P=0.040).CONCLUSION:OurobservationssuggestthattheAIRD1Ainactivationisassociatedwithlymphaticinvasion,lymphnodemetastasis,poorprognosis,andMMRdeficiencyingastricadenocarcinomas.