Consistent analysis of the expression of different PD-L1 antibodies in gastric adenocarcinoma
Purpose The purpose of this study was to in-vestigate programmed death ligand-1(PD-L1)expression in gastric adenocarcinoma(GAC)patients and the consistency of immunohistochemical(IHC)detection of four different clones of PD-L1 antibodies,so as to provide reference for the gradual standardization of PD-L1 IHC detection in gastric adenocarcino-ma and subsequent clinical studies.Methods This study col-lected surgically resected and pathologically confirmed specimens from 286 gastric adenocarcinoma patients,and specimens were stained with four antibodies:PD-L1 22C3,SP263,E1L3N and SP142.The consistency of the antibodies was statistically ana-lyzed under different critical values using two scoring criteria:comprehensive positive score(CPS)and tumor proportion score(TPS).Results Regardless of the TPS and CPS cut-off val-ues,the positive rate of 22C3 was the highest among the four an-tibodies.Consistency analysis showed that E1L3N had good con-sistency with SP142(κ=0.612)and SP263(κ=0.660)only when the cut-off value of CPS positive was 1.In addition,the consistency between the other antibodies was only moderate or poor.Conclusion The four PD-L1 antibodies exhibited incon-sistent concordance across various TPS and CPS positive thresh-olds,so it is not recommended to exchange reagents during clini-cal testing of GAC and the test results shall be documented in accordance with the specification.