Helicobacter pylori infection and PD-L1 expression in gastric cancer: A meta-analysis.

Background: High expression of programmed death ligand-1 (PD-L1) has been related to good response to immunotherapy patients with gastric cancer (GC). However, the influence of Helicobacter pylori (HP) infection on PD-L1 expression in GC remains unknown. A meta-analysis was performed to evaluate the association between HP infection and PD-L1 expression in GC.