Impact of PD-L1 Expression in Patients with Surgically Resected Non-Small-Cell Lung Cancer

Abstract

Background: Immunotherapy can become a crucial therapeutic option to improve the prognosis of patients with non-small-cell lung cancer (NSCLC). Here, we evaluated the impact of programmed cell death ligand-1 (PD-L1) expression in surgically resected NSCLCs. Methods: We estimated PD-L1 expression in 229 consecutive NSCLC specimens using rabbit polyclonal antibodies to human PD-L1 in a SP263 immunohistochemical assay and evaluated PD-L1 expression for potential associations with clinicopathological parameters and survival time. Results: PD-L1 expression was significantly higher in tumors from men or current smokers. Squamous cell carcinoma histology was independently associated with high PD-L1 expression according to multivariate analysis (p = 0.015). The 5-year survival rate of patients was 70%, and the difference in the 5-year survival rate according to PD-L1 expression was not statistically significant (high expression group [67%] vs. low expression group [68%]); however, the squamous cell carcinoma group exhibited significantly lower 5-year survival rates as compared to the non-squamous cell carcinoma group (53 and 71%, respectively; p = 0.026). Conclusion: Here, we revealed high PD-L1 expression and poor prognosis observed in patients with surgically resected squamous NSCLC as compared with non-squamous NSCLC. Our results support the identification of patient subsets that most likely respond to anti-PD-1 therapy as the first step in precision medicine.