Expression and clinical significance of PD-L1 and c-Myc in non-small cell lung cancer.

Abstract

It is known that there are insufficient prognostic factors for non-small cell lung cancer (NSCLC). It was reported that PD-L1 was a prognostic factor for NSCLC,and c-Myc regulated the expression of PD-L1. Herein, we investigated c-Myc and PD-L1 expression and their association with overall survival (OS) in NSCLC. Formalin-fixed paraffin-embedded specimens were obtained from 128 patients with surgically resected primary NSCLC. Immunohistochemistry was used to assess the expression of PD-L1 and c-Myc in this study. Pearson's Chi squared test or Fisher's exact test was used to analyze the correlation of the expression of PD-L1 and c-Myc with clinicopathologic features. The relationship between OS and the expression of PD-L1 and c-Myc was evaluated by the Kaplan-Meier method and Cox proportional hazards model, respectively. Positive expression of PD-L1 was detected in 59 patients (46.1%). Patients with negative expression of PD-L1 had remarkably longer OS than those with positive expression of PD-L1. The positive expression rate of c-Myc in NSCLC accounted for 58.6% (75/128) and its expression was significantly more frequent in males (p = 0.002) and patients with lymph node metastasis (p = 0.029). PD-L1 expression was positively correlated with c-Myc expression (r = 0.459, p < 0.001). The PD-L1 and c-Myc double-positive group had a worse prognosis than other subgroups (p < 0.05), and the PD-L1 and c-Myc double-negative group had a better OS than other subgroups (p < 0.05). Conjoint analysis of the expression of PD-L1 and c-Myc was a better prognostic approach for NSCLC patients.