Expression Of PD-1/PD-L1 In Glioma And Relationship With Survival Prognosis:A Meta-analysis

Objective: To evaluate the expression of PD-1 / PD-L1 in glioma and relationship with tumor grade and prognosis.Method Related studies searched from Pubmed,Embase,Web of Science,chinese biomedical database,China National Knowledge Infrastructure The Cochrane Library(Issue 4,2016)databases from inception to November 2016,and researchers screened literature,extracted data and evaluated the risk of bias of eligible studies dependently,then Meta-analysis was conducted by Revman 5.3 and R software.Result: A total of seventeen studies and 1179 gliomas were included.1.Meta-analysis showed that the expression rate of PD-L1 in tumor cells and tumor-infiltrating lymphocytes was 51%(RD=0.51,95%CI 0.41 to 0.61,P<0.001)and 68%(RD=0.68,95% CI 0.59 to 0.76,P<0.001),respectively;The expression rate of PD-1 in tumor cells and tumor-infiltrating lymphocytes was 51%(RD=0.51,95%CI 0.30 to 0.71,P<0.001).2.In terms of the relationship about PD-1/PD-L1 expression and WHO grade of gliomas,meta-analysis showed that the higher the grade,the higher the positive rate of PD-L1 expression,but the difference between adjacent grades was no statistical significance.(II vs III: RR=0.94,95%CI 0.72 to 1.23,P=0.66;III vs IV: RR=0.77,95%CI 0.56 to 1.05,P=0.10);II vs IV: RR=0.72,95%CI 0.53 to 1.97,P=0.03,respectively).3.Survival analysis showed that the prognostic risk of PD-L1 high expression group was higher than that of low expression group [HR=1.51,95%CI 1.21 to 1.79,P<0.001],the difference is statistically significant.Conclusion: PD-1/PD-L1 has a high positive expression rate in glioma cells and tumor infiltrating lymphocytes,and the level of expression is closely related to tumor grade.However,there was no significant difference in the expression of gliomas between adjacent grades.At the same time,the positive rate of PD-1/PD-L1 expression was an important factor in the prognosis of gliomas.