Clinicopathologic Significance And Prognostic Value Of Programmed Cell Death Ligand 1(PD-L1)in Patients With Hepatocellular Carcinoma:a Meta-analysis

Background:The results of many studies exploring the association between programmed death ligand-1(PD-L1)expression and the prognosis and clinicopathological characteristics of patients with hepatocellular carcinoma(HCC)are controversial.This comprehensive meta-analysis was performed to elucidate the clinical value of PD-L1 in HCC.Methods:Relevant studies were systematically searched in the Cochrane Library,EMBASE,and PubMed from its inception until June 27,2019.Eligible studies were evaluated for the prognostic effect of PD-L1 on the overall survival(OS),disease-free survival(DFS),and relapse-free survival(RFS)in HCC using a hazard ratio(HR)and its 95%confidence interval(95%CI).Additionally,the relationship between PD-L1 and clinicopathological features of HCC was examined with Odds ratio(OR)and its 95%confidence interval(95%CI)Results:Eighteen studies involving 2951 patients were enrolled in this meta-analysis.The pooled results showed that high PD-L1 expression was associated with poor OS(HR:1.42;95%CI:1.12-1.80;P=0.004).PD-L1 expression had no significant correlation with RFS(HR:1.14;95%CI 0.85-1.54;P=0.39),and DFS(HR:1.36;95%CI 0.81-2.28;P=0.25).Additionally,high PD-L1 expression was associated with alpha-fetoprotein(AFP;OR=1.46;95%CI:1.16-1,84;P=0.001),hepatitis(OR:0.72;95%CI:0.54-0.98;P=0.03),tumor differentiation(OR=0.68;95%CI:0.55-0.84;P=0.03),and tumor-infiltrating lymphocytes(OR:3.39;95%CI 1.06-10.91;P=0.04).However,PD-L1 expression had no correlation with age,number of tumors,gender,tumor size,liver cirrhosis,vascular invasion,tumor encapsulation,or TNM stage.Conclusions:This meta-analysis indicated that patients with PD-L1 overexpression have shorter overall survival.Moreover,overexpression of PD-L1 was highly associated with poor tumor differentiation,hepatitis,AFP and tumor-infiltrating lymphocytes.