F-157 Clinical characteristics of lung cancer with programmed death-ligand 1 expression = F-157 Clinical characteristics of lung cancer with programmed death-ligand 1 expression

다국어 초록 (Multilingual Abstract)

Background: Programmed death-ligand 1 (PD-L1) is a transmembrane protein that binds to the programmed death-1 (PD-1) receptor and anti-PD-1 therapy enables the immune response against tumors. The aim of this study was to assess the clinical and pathological characteristics of PD-L1 positive lung cancer.
Methods: We retrospectively reviewed the medical record of pathologically proven lung cancer patients, and collected 267 cases of formalin-fixed, paraffin-embedded tissue sample from single institution. PD-L1 expression was detected by qualitative immunohistochemistry using Monoclonal Mouse Anti-PD-L1, Clone 22C3 and determined by using Tumor Proportion Score (TPS), which is the percentage of viable tumor cells showing partial or complete membrane staining.
Results: A total of 267 patients were enrolled and major histologic type was adenocarcinoma (69.3%). Most were smoker (67.4%) and clinical stage IV (60.7%) with 31 (11.6%) cases of EGFR mutation and 17 (6.4%) cases of ALK rearrangement. The patients who showed TPS ≥ 1% and 50% were 116 (42%) and 58 (21%), respectively. TPS ≥ 1% group was older than TPS ＜ 1% group (64.83±9.38 vs. 61.73±10.78, p=0.014). In histological grade, the proportion of poorly differentiated tumor was significantly higher in PD-L1 positive than negative group (40.8% vs. 25.8% based on TPS ≥ 1%, p=0.020 and 53.2% vs. 27.2% based on TPS ≥ 50%, p=0.004). But there was no difference in smoking, histologic type, EGFR or ALK status between two groups.
Conclusions: PD-L1 expression was observed more frequently in poorly differentiated grade lung cancer.