Gastric Cancer and the Gut Microbiota

Abstract

Recently, interest has focused on the association between the gut microbiota and human malignancies. Gastric cancer is one of the most common malignancies in the world. However, despite Helicobacter pylori being a well-known carcinogen for gastric cancer, studies of the association between the gut microbiota and gastric cancer are relatively few. The intestinal microbial diversity of H. pylori-infected subjects is significantly higher than that of non-infected subjects, and the abundance of the genus Streptococcus is significantly higher than that in H. pylori-infected subjects without atrophic gastritis. The gastric microbiota of patients with gastric cancer is characterized by the increase of oral bacteria, such as Streptococcus and Prevotella. An increase in oral bacteria is also a well-known characteristic of the intestinal flora of patients with colonic cancer. These findings might suggest that the progress of gastric glandular atrophy is associated with the development of colonic cancer as well as intestinal-type gastric cancer.