Paradoxical change in microbiome structure tied to gastric cancer, atrophy

A recent study has found a paradoxical change in the microbiome structure in the development of severe gastric mucosal atrophy, which appears to have a significant association with the progression of gastric atrophy and gastric cancer risk.

The investigators examined bacterial communities of the gastric mucosa in the antrum of 182 cancer-free patients using 16S rRNA sequencing. They correlated the result with clinicopathological characteristics, histologic, and serological degrees of Helicobacter pylori (H. pylori)-related gastritis.

Bacterial alpha diversity measures were significantly lower in H. pylori clinical test positives than that in the negatives. Lower bacterial alpha diversity measures correlated with the degree of histologic gastritis in the antrum, while higher measures correlated with the degree of serological gastritis.

Histologic gastritis (active gastritis, atrophy) showed a significant association with lower Shannon index (t=‒4.37; p<0.0001) in multiple regression analysis, indicating bacterial alpha diversity. On the other hand, serological gastritis correlated with higher Shannon index (t=2.98; p<0.0001).

Notably, an association was noted between the abundance of Bacillus, Actinobacillus, and Streptococcus and the degree of serological gastritis.

“[The risk] of H. pylori-related gastroduodenal diseases is influenced by the degree of chronic gastritis, while other microbes reside in gastric mucosa may be relevant to this process,” the investigators said.