The potential prognostic and predictive roles of programmed cell death protein 1 expressed by tumor-infiltrating lymphocytes in solid tumors:a meta-analysis

Aim:Several previous studies have evaluated the potential role of programmed cell death protein 1(PD-1)expressed by tumor-infiltrating lymphocytes(TILs)in various solid tumors and performed its prognosis role in patients’survival with inconsistent results.This study aims to further systematically evaluate the association of PD-1 by TILs with clinicopathological parameters and clinical outcomes in solid tumor patients.Methods:A comprehensive search was conducted in PubMed,Embase,Web of Science,CNKI and Wanfang databases for relevant studies.The potential prognostic and predictive roles of PD-1 were assessed by pooled hazard ratio(HR),odds ratio(OR)and 95%confidence intervals(CI).A total of 1863 patients were selected for in-depth analysis.Results:The results demonstrated that PD-1 by TILs was correlated to overall survival for ovarian cancer(HR=0.40,95%CI:0.26-0.61,P<0.00001).Higher PD-1 expression was associated with lymph node metastasis(OR=2.55,95%CI:1.22-5.29,P=0.01)and tumor grade(OR=3.08,95%CI:2.07-4.57,P<0.00001).Conclusion:The prognostic role of PD-1 by TILs is variant in different tumor types,which highlights the role of PD-1 by TILs as a potential predictive and prognostic biomarker and the development of strategies against the PD-L1/PD-1 axis would be a promising therapeutic target for some solid tumors.