The correlation and overlaps between PD-L1 expression and classical genomic aberrations in Chinese lung adenocarcinoma patients: a single center case series

Abstract

Objective To investigate the correlation and overlaps between PD-L1 expression and classical genomic aberrations in Chinese lung adenocarcinoma (LADC) patients. Methods We reviewed 428 consecutive, surgically resected cases of LADC from October 2015 to December 2016 from our center. PD-L1 expression was evaluated based on tumor proportion score (TPS). Correlation and co-occurrence of PD-L1 expression level with those of classical driver genes, such as EGFR, ALK, ROS-1, and KRAS and with clinical variables and disease-free survival (DFS) were analyzed. Results Seventy of the 428 cases (16.4%) showed TPS = 1%, and 21 cases (4.9%) showed TPS = 50%. PD-L1 positive expression was significantly associated with male gender, smoking, advanced TNM stage, and solid histologic subtype. Both TPS = 1% and = 50% were correlated with the absence of an EGFR mutation (P < 0.001) and the presence of ALK rearrangement ( P = 0.024). KRAS mutation was associated with TPS = 50% (P = 0.035). PD-L1 positivity commonly overlapped with the alterations of classical driver oncogenes (58.5% with TPS = 1% and 42.9% with TPS = 50%). Approximately three-quarters of PD-L1 positive cases co-occurred with classical therapeutic-gene aberrations in cases with stage III/IV cancer or cancer progression. LADC could be divided into four subgroups based on the expression profile of current routine biomarkers for potential therapeutic strategies. Conclusions PD-L1 expression is not only closely correlated with classic gene alterations but also commonly overlaps with the aberrations of classical driver oncogenes in Chinese LADC patients. These findings provide a useful overview of clinical strategies that rely on the profile of routinely used molecular biomarkers.