The Gastric Microbiome Communities and Endoscopic Mucosal Morphologies Associated with Premalignant Conditions

The risk of Helicobacter pylori (H. pylori)-related gastric tumorigenesis is closely associated with the degree of chronic gastritis, although other gastric mucosa microbes may be relevant in this process. The morphological identification of the gastric mucosa associated with the cancer-promoting microbiome may have important implications for gastric cancer prevention. This study characterized gastric mucosa microbiome communities in relation to their mucosal morphologies. A total of 94 biopsies from non-neoplastic gastric bodies underwent 16S rRNA sequencing. Microbiome structures were characterized in relation to their mucosal morphologies, which were obtained using narrow-band imaging with magnifying endoscopy. H. pylori infection- and inflammatory mucosa-associated gastric mucosal morphologies exhibited decreased bacterial alpha diversity measures and an increase in the abundance of the Helicobacter genus, while the mucosal morphology associated with severely atrophic mucosa exhibited increased bacterial alpha diversity measures and a decrease in the abundance of the Helicobacter genus. This type of mucosal morphology was also associated with increased levels of well-known gastric cancer-related bacteria, e.g., Streptococcus. The microbial dysbiosis associated with gastric mucosa morphology also correlated well with the occurrence of gastric cancer and the DNA methylation status. Our results suggest that gastric microbiome communities correlate well with their premalignant condition-associated mucosal morphologies.