H. Pylori Infection Studied for Association With Colorectal Cancer

Helicobacter pylori (H pylori) infection is a strong causal promoter of colorectal carcinogenesis, researchers reported in a study published in the journal Gut.

“In our study, we identify H. pylori-specific alterations in gut homeostasis that contribute to colorectal carcinogenesis in mouse models of colorectal cancer as well as in human samples, and are reversible on H. pylori eradication,” wrote corresponding author Markus Gerhard, MD, a professor at Technical University of Munich in Germany, and study coauthors. “These findings provide a basis for assessing H. pylori status for gastric and for colon cancer prevention programs.”

H. pylori is a known key risk factor for gastric cancer, but mechanisms behind the increased risk have not been understood. For this study, researchers infected Apc-mutant mice with H. pylori and analyzed changes in their intestinal immune responses and epithelial signatures. Microbial signatures were also evaluated in germ-free mice and experiments with stool transfer.

H. pylori infection accelerated tumor development in the mice, the study showed.

“We identified a unique H. pylori-driven immune alteration signature characterized by a reduction in regulatory T cells and pro-inflammatory T cells,” researchers wrote. “Furthermore, in the intestinal and colonic epithelium, H. pylori induced pro-carcinogenic STAT3 signaling and a loss of goblet cells, changes that have been shown to contribute—in combination with pro-inflammatory and mucus degrading microbial signatures—to tumor development.”

Samples from colon biopsies in human patients with H. pylori infection revealed similar immune and epithelial alterations, researchers reported.

Early antibiotic eradication of H. pylori infection normalized tumor incidence to the level of uninfected controls, the study found.

“In summary, our study provides solid experimental evidence that H. pylori infection accelerates intestinal and colonic tumor development, and offers insight into the underlying mechanisms,” researchers wrote. “We suggest H. pylori screening and eradication as a potential measure for colorectal cancer prevention strategies.”

Reference
Ralser A, Dietl A, Jarosch S, et al. Helicobacter pylori promotes colorectal carcinogenesis by deregulating intestinal immunity and inducing a mucus-degrading microbiota signature. Gut. 2023;72(7):1258-1270. doi:10.1136/gutjnl-2022-328075