简介：Blockadeofimmunecheckpointshasrecentlyemergedasanoveltherapeuticstrategyinvarioustumors.Inparticular,monoclonalantibodiestargetingprogrammedcelldeath1(PD-1)oritsligand(PD-L1)havebeenmoststudiedinlungcancer,andPD-1inhibitorsarenowestablishedagentsinthemanagementofnon-smallcelllungcancer(NSCLC).ThereportsonhighprofileclinicaltrialshaveshowntheassociationofPD-L1expressionbyimmunohistochemistry(IHC)withhigheroverallresponseratestothePD-1/PD-L1axisblockadesuggestingthatPD-L1expressionmayserveasapredictivemarker.Unfortunately,however,eachPD-1orPD-L1inhibitoriscoupledwithaspecificPD-L1antibody,IHCprotocolandscoringsystemforthebiomarkerassessment,makingthehead-to-headcomparisonofthestudiesdifficult.Similarly,multipleclinicalseriesthatcorrelatedPD-L1expressionwithclinicopathologicand/ormolecularvariablesand/orsurvivalhavereportedconflictingresults.Thediscrepancycouldbeexplainedbythedifferencesinethnicityand/orhistologictypesincludedinthestudies,butitappearstobeattributedinparttothedifferencesinPD-L1IHCmethods.Thus,orchestratedeffortstostandardizethePD-L1IHCarewarrantedtoestablishtheIHCasapredictiveand/orprognosticbiomarkerinNSCLC.