Chang CY, Lai YC, Wei YF, et al. - Researchers investigated the role of programmed cell death-ligand 1 (PD-L1) expression in non-small cell lung cancer (NSCLC) tumors with epidermal growth factor receptor (EGFR) mutation as well as its impact on clinical results in this retrospective study. Participants were newly diagnosed cases with metastatic NSCLC with sensitizing EGFR mutations managed with standard EGFR-tyrosine kinase inhibitor (TKI) treatment for mutant adenocarcinoma as the first-line therapy. EGFR-TKIs were taken by all 114 participants as first-line therapy and Kaplan-Meier analysis revealed no significant difference in progression-free survival among groups with different PD-L1 expression status. Findings revealed that presence of PD-L1 expression in patients with metastatic NSCLC and EGFR mutations was not uncommon but PD-L1 expression had no significant impact on clinical results in patients undergoing standard initial treatment.