Impact of Helicobacter pylori on immunotherapy in gastric cancer

This study reviews the contrasting finding regarding the impact of Helicobacter pylori infection on the efficacy of immunotherapy in gastric cancer (GC). While a large retrospective study reported a positive association between H. pylori infection and progression-free survival (PFS)/overall survival (OS) in patients with GC undergoing PD-1/PD-L1 therapy, previous studies had given rise to a contrary outcome. Potential explanations of the inconsistency include the divergent immune responses induced by different H. pylori status (current infection, postinfection and negative status) directly, as well as the indirect influence of gut microbiota alterations. Tumor molecular subtypes, particularly Epstein-Barr virus (EBV) infection status, may also play a role in the discrepancy by altering the profile of immune infiltration. However, data on EBV status are absent in studies showing H. pylori infection as an unfavorable factor for GC immunotherapy. Moreover, a combined positive score (CPS) <1 might exert a positive influence, as more patients with CPS<1 enrolled in the study reported a positive association between H. pylori infection and immunotherapy. The review highlights the need for further research to clarify the complex interplay between H. pylori infection, immune response, and immunotherapy efficacy in GC, aiming to develop more targeted and personalized treatment strategies.