Revisiting the impact of clinicopathologic characteristics in PD-L1 profile in a large cohort of non-small cell lung cancer.

Background: Immunotherapies using anti-programmed cell death ligand-1 (PD-L1) agents have recently shown remarkable outcomes in patients with non-small cell lung cancer (NSCLC). However, there was a poor correlation between PD-L1 expression and treatment response. Many researchers have focused on the clinicopathological factors associated with prognosis, but the results are conflicting. In the present study, we investigated the clinicopathological significance of PD-L1 overexpression in NSCLC cells. Methods: In total, 344 NSCLC cases with PD-L1 assays were retrospectively analyzed. PD-L1 expression was evaluated via immunohistochemical staining using antibodies against SP263 and SP142. The correlation between clinicopathological factors and PD-L1 expression was analyzed for various clinicopathological features. Results: PD-L1 expression significantly correlated with several poor clinicopathological factors, including the solid component of adenocarcinoma, lymphatic invasion, and recurrence. Squamous cell carcinoma, older age, and male sex were also associated with PD-L1 expression. However, we could not observe correlation between PD-L1 expression and disease-free survival (DFS). A novel finding was that lower metastasis was associated with high PD-L1 expression of SP142 in tumor-infiltrating immune cells (ICs). Conclusions: PD-L1 expression in NSCLC is associated with adverse clinicopathological features and recurrence; therefore, it could be utilized to predict poor prognosis. Furthermore, the high PD-L1 expression of SP142 in tumor-infiltrating ICs could be a potential marker for low metastasis.