PD-L1 expression and overall survival in Asian and western patients with gastric cancer.

Aim: Data are limited on PD-L1 expression and its association with overall survival (OS) in gastric cancer (GC) patients receiving routine care in different regions. Materials & methods: In a retrospective study, PD-L1 expression was assayed using the 22C3 pharmDx on GC tumor samples collected between 2003 and 2017 at South Korean and US cancer centers. PD-L1 positivity was defined as combined positive score (CPS) ≥1. The relationship between PD-L1 and OS was analyzed. Results: Of 574 GC tumor samples, 67.4% were CPS ≥1 (68.7% in Korean and 65.7% in US patients). PD-L1 expression was not associated with OS (adjusted hazard ratio: 0.94; 95% CI: 0.75-1.17). Conclusion: PD-L1 prevalence and its association with OS was similar between South Korean and US GC patients.

Prognostic significance of T-cell-inflamed gene expression profile and PD-L1 expression in patients with esophageal cancer.

PURPOSE: The ability of the T-cell-inflamed gene expression profile (GEP) to predict clinical outcome in esophageal cancer (EC) is unknown. This retrospective observational study assessed the prognostic value of GEP and programmed death ligand 1 (PD-L1) expression in patients with EC treated in routine clinical practice. METHODS: Tumor samples of 294 patients from three centers in Denmark, South Korea, and the United States, collected between 2005 and 2017, were included. T-cell-inflamed GEP score was defined as non-low or low using a cutoff of -1.54. A combined positive score (CPS) ≥10 was defined as PD-L1 expression positivity. Associations between overall survival (OS) and GEP status and PD-L1 expression were explored by Cox proportional hazards models adjusting for age, sex, histology, stage, and performance status. RESULTS: Median age was 65 years; 63% of patients had adenocarcinoma (AC) and 37% had squamous cell carcinoma (SCC). Thirty-six percent of tumors were GEP non-low, with higher prevalence in AC (46%) than SCC (18%). Twenty-one percent were PD-L1-positive: 32% in South Korean samples versus 16% in non-Asian samples and 26% in SCC versus 18% in AC. GEP scores and PD-L1 CPS were weakly correlated (Spearman's R = 0.363). OS was not significantly associated with GEP status (non-low vs low; adjusted hazard ratio, 0.91 [95% CI, 0.69-1.19]) or PD-L1 expression status. CONCLUSION: Neither GEP nor PD-L1 expression was a prognostic marker in Asian and non-Asian patients with EC.