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

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. 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.