Quantification Of Pd-L1 Mrna Expression In Lung Adenocarcinoma With Egfr Mutation.

e23261Background: Programmed death-ligand 1 (PD-L1) expression on immunohistochemistry is associated with response to PD-1 blockade.However, the molecular mechanism and clinical significance of PD-L1 mRNA expression and the roles of cell apoptosis and other biomarkers have not been adequately studied in patients with epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma. Methods: We studied 31 patients with recurrent postoperative EGFR-mutant lung adenocarcinoma (exon 19 deletion in 16, L858R in 14, G719C in 1) treated with gefitinib between January 2008 and January 2016. Using KCL22 cell line for calibration, we utilized relative quantification of PD-L1 mRNA expression on PCR analysis of formalin-fixed paraffin-embedded slides of surgical specimens to determine PD-L1 mRNA expression in and around the tumor. In addition, we assessed correlations of PD-L1 mRNA expression with expressions of BIM, PUMA, HER2, MET, EGFR, and VEGFA. Results: PD-L1 mRNA expression was noted in the tumor in 11 of 31...