Effect of Helicobacter Pylori infection on immunotherapy for gastrointestinal cancer: a narrative review.

Immunotherapy for gastrointestinal cancers has elicited considerable amount of attention as a viable therapeutic option for several cancer types. Gut microbiome as a whole plays a critical role in shaping immune responses and influencing cancer progression. Recent evidence suggests that Helicobacter pylori (H. pylori), may influence immunotherapy efficacy by modulating the tumor microenvironment. Infection with H. pylori is common as it affects approximately 50% of the global population and remains the leading risk factor for gastric cancer. Interestingly, recent clinical and preclinical data has associated H. pylori with colorectal cancer carcinogenesis. Gut microbiome appears to be a modulator of the relationship between the immune system, gastrointestinal cancer development and existing therapies. Infection with H. pylori may affect immunotherapy results in both gastroesophageal and colorectal cancer; favorable results were noticed in H. pylori positive patients with gastric cancer, while in colorectal cancer patients the pathogen seemed to impede immunotherapy's action. This article aims to review current data on the role of H. pylori in triggering gastric inflammation and cancer, as well as its potential involvement in colorectal cancer development. Additionally, it seeks to highlight the impact of H. pylori infection on the response to immunotherapy in gastrointestinal cancers.