The Role of the Microbiome in Gastric Cancer: A Systematic Review

The aim of this article is investigating the microbiome's effect on the development and progression of gastric cancer can substantially improve preventing, diagnosing, and treating this disease.

In this review article, after analyzing the studies searched in PubMed and Scopus databases, related articles have been selected from 2015 to 2022, and based on this, the carcinogenic role of the gastric microbiome, which is caused by complex communities of bacteria, viruses, and fungi, were investigated.

With the discovery of Helicobacter Pylori (H. pylori) in 1982, the theory that the stomach is sterile was refuted, leading to a period of gastric microbial research. In addition, advances in nucleic acid sequencing techniques indicated that a complex community of microbes might coexist with H. pylori in the gastric area. Numerous studies have examined the crucial function of H. pylori in gastric cancer, particularly strains that harbor the Cag A and Vac A genes. These bacteria contribute to carcinogenesis by altering gastric acidity and, consequently, the organization of the gastric microbiota. While there is increasing evidence that microorganisms other than H. pylori and their metabolites play a significant role in gastric carcinogenesis, the function of the viral and fungal microbiome in gastric cancer has received less consideration.

More investigations are needed to provide new insights into diagnosing, preventing, and treating gastric cancer. Also, clinical research design related to the interaction between the gastric microbiome genome and the human host genome, besides identifying the signaling pathways involved in the pathogenesis of gastric cancer, can be practical.