RESUMEN
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.