| Objectives:Programmed cell death ligand 1(PD-L1)is up-regulated in a variety of solid malignancies,including gastric cancer(GC).But,in terms of the clinicopathology and prognosis of GC,the worth of PD-L1 expression continues to be unsure.In this paper,we aimed to assess their relationship through a meta-analysis.Method:The literatures about the expression of PD-L1 in gastric cancer,published up to December 2019,were searched in Pub Med,Embase,Web of Science and the Cochrane Library.The hazard ratio(HR)with 95%confidence interval(95%CI)for overall survival(OS)and disease-free survival(DFS)was computed by enrolled studies.Moreover,the odds ratio(OR)was used to estimate the association between the clinicopathologic parameters of participants and PD-L1 expression.Results:A total of 34 studies,involving 7454 gastric cancer subjects,were selected to the meta-analysis.The pooled results revealed that PD-L1 expression was remarkably bound up with the OS in gastric cancer(HR=1.35,95%CI:1.13-1.61,P=0.0009),but not in DFS(HR=1.11,95%CI:0.73-1.67,P=0.62).Moreover,we also suggested that a high density of CD8~+tumor-infiltrating lymphocytes(TILs)was related to a better OS(HR=0.57,95%CI:0.48-0.67,P<0.00001).Besides,the results suggested that gastric cancer patients with the male,age≥60,intestinal type,deeper tumor infiltration,lymph node metastasis positivity,proximal tumor,Epstein-Barr virus positive(EBV~+),high density of CD8~+TILs,microsatellite instability(MSI)were prone to express PD-L1.Conclusion:The results suggested that PD-L1 expression positivity may be an important biomarker for poor prognosis of gastric carcinoma.Gastric cancer patients,especially those with a high density of CD8~+TILs、EBV~+and MSI,may potentially benefit from anti-PD-1/PD-L1 immunotherapy. |
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