PD-L1 over-expression is associated with a poor prognosis in Asian non-small cell lung cancer patients

The prognostic role of programmed cell death-ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC) remains controversial. This meta-analysis was conducted to clarify the association of PD-L1 with survival in NSCLC patients.Relevant studies were collected from PubMed, Embase and Web of Science. Only studies in which PD-L1 expression was detected by immunohistochemical staining in NSCLC patients correlated with patient survival data were included. Stata 12.0 was performed in this meta-analysis.Fifteen studies with 3116 patients were included in this meta-analysis. The combined hazard ratio (HR) of 1.18 (95%CI, 0.90-1.56; P>0.05) shows that PD-L1 over-expression in NSCLC patients didn't associate with overall survival (OS). However, subgroup analysis indicated that PD-L1 over-expression was correlated with poor OS in Asian patients (HR=1.84, 95%CI: 1.14-2.28; P<0.001). Moreover, the results suggested that a significant relationship between PD-L1 expression and OS was also showed in studies with late stage (HR=1.27, 95%CI: 1.06-1.48; P=0.031), poor tumor differentiation (HR=1.86, 95%CI: 1.35-2.64; P=0.001) and anaplastic lymphoma kinase (ALK) translocation (HR=2.58, 95%CI: 1.03-5.78; P=0.028).PD-L1 over-expression is correlated with a poor prognosis in Asian NSCLC patients.