Study Links Mouth Bacteria to Gastric Cancer in Groundbreaking Research

New research published in the journal Cell Reports Medicine has revealed a significant association between oral bacteria and gastric cancer, potentially opening new pathways for early detection and treatment.

Chinese researchers from BGI Genomics conducted a comprehensive analysis of 404 samples from patients with either gastric cancer or chronic gastritis, examining both gut microbiome in stool and oral microbiome from saliva and tongue samples.

The findings were striking: researchers identified 28 different gut microbial species that varied between the two groups. Most notably, the majority of these were oral bacteria, including Streptococcus (which can cause strep throat), lactobacillus, and other lactic acid bacteria.

Twenty species were found in both the saliva and stool samples, with these bacteria appearing significantly more frequently in the gut of gastric cancer patients. The genetic similarities between oral bacteria and gut bacteria in the same individuals strongly suggest a direct transmission pathway from mouth to stomach.

“Collectively, these findings underscore the critical role of the oral-gut microbiome axis in gastric cancer,” the researchers concluded in their publication.

While the cross-sectional nature of the study cannot definitively prove causation, it demonstrates a strong association that merits further investigation. The research potentially offers a new angle on gastric cancer development, which ranks among the more lethal forms of cancer worldwide due to challenges in early detection.

Dr. Brian Slomovitz, director of gynecologic oncology and co-chair of the Cancer Research Committee at Mount Sinai Medical Center in Miami Beach, who was not involved in the study, described the findings through an “initiator-promoter” model.

“[The study] demonstrates how the microbiome of one area of the body can migrate and affect the ability of cancers to develop in another part of the body,” Slomovitz explained. “The initiator in gastric cancers is usually inflammatory, such as H.pylori infection. This inflammation leads to damaged mucosal cells where the lactic acid-producing bacteria can colonize. This helps to explain why cancers still develop even after treating H. pylori infection.”

The research opens promising avenues for both detection and treatment. The possibility of using saliva samples for early cancer detection could revolutionize screening protocols, potentially identifying the disease even in pre-cancerous states. This non-invasive approach could significantly improve early intervention rates for a cancer that is often diagnosed in advanced stages.

Dr. Marc Siegel, a senior medical analyst, emphasized the growing awareness around the gut microbiome’s importance to overall health. “There is a correlation between the bacteria found in the gut and neurogenerative disease and increased cancer risk,” he noted. “It is very important that we work toward a healthy microbiome in the gut to decrease the risk of inflammation and cancer.”

The implications extend beyond detection to potential treatment approaches. Slomovitz suggested, “Perhaps we will learn that by altering the microbiome, we can help better treat cancers (in combination with immunotherapy or chemotherapy) or even prevent cancer.”

This research aligns with the emerging field of microbiome studies, which has already demonstrated connections between gut bacteria and various health conditions, including inflammatory bowel disease, diabetes, and neurological disorders.

However, both experts cautioned that while the findings establish a foundation for future research, they aren’t yet ready for clinical application. Additional studies will be needed to validate these results and develop standardized testing and treatment protocols.

The study adds to growing evidence that the human microbiome—the complex ecosystem of microorganisms living in and on our bodies—plays a far more significant role in disease development and progression than previously understood, potentially transforming approaches to cancer prevention, detection, and treatment in coming years.