Prognostic value of programmed death-ligand 1 expression in patients with esophageal squamous cell carcinoma

Background To investigate the expression of PD-L1(programmed death-ligand 1)in patients with esophageal squamous cell carcinoma (ESCC) and its clinical significance. Methods The tissue expression of PD-L1 protein in 139 cases of ESCC and 50 adjacent non-malignant epithelial tissues (> 5 cm from the tumor resection margins) were identified by immunohistochemical staining. Subsequently, the relationship between expression and the observed clinical characteristics was analyzed. Results The positive expression rate of PD-L1 protein was increased in tumor tissues compared to that of adjacent noncancerous mucosa tissues (40.3% vs. 22.0%, P < 0.05). The findings also indicated that PD-L1 protein expression had no significant correlation with age, gender, tumor location, differentiation and lymph node (N) status (P > 0.05). The 91 months follow-up Kaplan-Meier survival analysis showed that patients in positively expressed PD-L1 group experienced a lower survival rate compared to their negatively expressed PD-L1 counterparts (32.1% vs. 48.2%, P < 0.05). The COX regression analysis results suggested that PD-L1 represented an independent prognosis factor for ESCC. Conclusions The findings indicated that PD-L1 plays an important role in the progression of ESCC and might represent a potential therapeutic and prognostic target for ESCC patients.