The relationship between PD-L1 expression and tumor driver gene mutations and survival in non small cell lung carcinoma

To explore the relationship between PD-L1 expression and gene mutations and survival. PD L1, ALK and MET protein expression were detected by immunohistochemistry, and EGFR gene mutation by RT-PCR in 209 cases of NSCLC. The correlations between PD-L1 expression and gene mutations, clinicopathological features and survival was analyzed. PD-L1 was expressed in 99/209 cases (47.4%) of NSCLC, including score 1 (≥ 1% to < 5%) 23 cases (11%), score 2 (≥ 5% to < 50%) 36 cases (17.2%), and score 3 (> 50%) 40 cases (19.1%). There were 89 cases (42.6%) of EGFR mutation, 12 (5.7%) of ALK and 90 (43.1%) of MET protein positive. PD-L1 positive expression occurred more frequently in men and non-adenocarcinoma, and was negatively correlated with EGFR mutation and histological differentiation of NSCLC. PD-L1 expression was concordant in primary and metastatic cancers. There was no any effect of PD-L1 expression on overall survival of patients with NSCLC. These results suggested that PD-L1 expression is not an independent risk factor for survival of patients with NSCLC. Because of mutual complementarities of PD-L1 expression and EGFR mutation in NSCLC, both should be simultaneously detected for the patients to achieve eligible treatments.