[Influence of genetic variation of programmed death-ligand 1 (PD-L1) on the prognosis of patients with non-small cell lung cancer who received platinum-based adjuvant chemotherapy].

Objective: The aim of present study was to investigate the influence of genetic variation of programmed death-ligand 1 (PD-L1) on the prognosis of patients with non-small cell lung cancer (NSCLC) who received platinum-based adjuvant chemotherapy. Methods: This study was designed as a retrospective analysis, and a total of 278 patients with postoperative NSCLC who received platinum-based adjuvant chemotherapy from January 2012 to December 2018 in the Department of Respiratory Medicine of the First affiliated Hospital of Zhengzhou University were included in this study. Biological specimens of the patients were collected during hospitalization. Recurrence status and adverse reactions were evaluated in the hospital during adjuvant chemotherapy. Survival data of the patients were obtained through telephone follow-up after completing the fixed cycle of adjuvant chemotherapy. DNA extracted from the collected hematological specimens was genotyped for PD-L1 gene polymorphism. Additionally, postoperative cancer tissue specimens from 68 patients were collected for RNA extraction in order to perform the PD-L1 mRNA expression analysis. The univariate analysis of genotypes and prognosis was carried out by Kaplan-Meier survival analysis. Results: Prognostic results indicated that the median disease-free survival (DFS) of the 278 patients with NSCLC was 3.2 years and the median overall survival (OS) was 4.9 years. The prevalence of -1813G>C polymorphism were: GG genotype 173 cases (62.23%), GC genotype 92 cases (33.09%), CC genotype 13 cases (4.68%), the minor allele frequency was 0.21, the distribution of the three genotypes was in accordance with Hardy-Weinberg Equilibrium (P=0.864). In view of the rare frequency of CC genotype, GC and CC genotype were merged in the following analysis. The survival analysis results of the two genotype groups suggested that the median DFS of patients with GG and GC/CC genotype was 2.7 and 4.0 years, which was statistically significant (P=0.013). Furthermore, the median OS of patients with GG and GC/CC was 4.0 and 5.4 years respectively, which was statistically significant as well (P=0.009). However, the safety analysis failed to find the significant association between the polymorphism and adverse events (P>0.05). Interestingly, expression analysis of RNA extracted from cancer tissues specimens indicated that the PD-L1 mRNA expression of the patients with GG genotype were significantly higher than those of the GC/CC genotype (3.67±0.65 vs 2.69±0.78, P C polymorphism of PD-L1 gene.