Association with PD-L1 Expression and Clinicopathological Features in 1000 Lung Cancers: A Large Single-Institution Study of Surgically Resected Lung Cancers with a High Prevalence of <i>EGFR</i> Mutation

• Main Authors: Seung Eun Lee, Yu Jin Kim, Minjung Sung, Mi-Sook Lee, Joungho Han, Hong Kwan Kim, Yoon-La Choi
• Format: Article
• Language: English
• Published: MDPI AG 2019-09-01
• Series: International Journal of Molecular Sciences
• Subjects: lung cancer; immunotherapy; pd-l1; <i>egfr</i> mutation
• Online Access: https://www.mdpi.com/1422-0067/20/19/4794

Programmed cell death ligand 1 (PD-L1) expression is an important biomarker for predicting response to immunotherapy in clinical practice. Hence, identification and characterization of factors that predict high expression of PD-L1 in patients is critical. Various studies have reported the association of PD-L1 expression with driver genetic status in non-small cell cancer; however, the results have been conflicting and inconclusive. We analyzed the relationship between PD-L1 expression and clinicopathological factors including driver genetic alterations in 1000 resected lung cancers using a clinically validated PD-L1 immunohistochemical assay. PD-L1 expression was significantly higher in squamous cell carcinoma (SCC) compared to adenocarcinomas. PD-L1 expression in adenocarcinoma was associated with higher N-stage, solid histologic pattern, <i>EGFR</i> wild type, and <i>ALK</i> positive, but no significant association with the clinicopathological factors in SCC. <i>EGFR</i> mutant adenocarcinomas with distinctive clinicopathologic features, especially solid histologic pattern and higher stage showed higher PD-L1 expression. To the best of our knowledge, this study is the largest to evaluate the association between PD-L1 expression and clinicopathological and molecular features in lung cancer with a highly prevalent <i>EGFR</i> mutation. Therefore, our results are useful to guide the selection of lung cancer, even <i>EGFR</i>-mutated adenocarcinoma patients with PD-L1 expression, for further immunotherapy.