Programmed Death-Ligand 1 Expression Predicts Tyrosine Kinase Inhibitor Response and Better Prognosis in a Cohort of Patients With Epidermal Growth Factor Receptor Mutation-Positive Lung Adenocarcinoma

Micro-Abstract The oncogenic driver epidermal growth factor receptor (EGFR) mutations upregulate immune checkpoint proteins programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) in in vitro and in vivo models of non–small-cell lung cancer (NSCLC). Immunohistochemistry revealed that PD-L1 and PD-1 were positive in 53.6% and 32.1% of tumor specimens in a cohort of 56 patients with NSCLC carrying EGFR mutations, respectively. PD-L1 expression correlated with a better response to EGFR tyrosine kinase inhibitors and longer survival.