Bacteria in your mouth may travel to the gut and trigger stomach cancer, research finds

New research is suggesting a strong association between mouth bacteria and gastric cancer.

The study, published in the journal Cell Reports Medicine, examined the gut microbiome in stool and the oral microbiome from saliva and the tongue.

The China-based researchers with BGI Genomics analyzed 404 samples from Chinese patients with gastric cancer in one group and chronic gastritis in another.

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Gut microbes were different in gastric cancer, the researchers found, unveiling 28 varying gut species. 

Most were oral bacteria, including Streptococcus — bacteria that can sometimes cause strep throat — lactobacillus and other lactic acid bacteria.

Twenty oral-gut species were found in both saliva and stool and were more common in the gut of gastric cancer patients.

The findings suggest the transmission of these bacteria from mouth to gut, after finding that the oral bacteria matched closely to the gut bacteria in the same person, according to genetic comparisons.

The researchers suggest that saliva and stool samples could help indicate patterns that are linked to stomach cancer, although more research is required before testing is ready for clinical use.

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"Collectively, these findings underscore the critical role of the oral-gut microbiome axis in [gastric cancer]," the researchers concluded in the study publication.

Since this is a cross-sectional analysis, the results cannot prove that these bacteria cause cancer, but they do suggest a strong association.

Dr. Brian Slomovitz, director of gynecologic oncology and co-chair of the Cancer Research Committee at Mount Sinai Medical Center in Miami Beach, Florida, talked about the "initiator-promoter" model of this study in an interview with Fox News Digital.

"[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," said Slomovitz, who was not involved in the new study. 

"The initiator in gastric cancers is usually inflammatory, such as H.pylori infection," he continued. 

"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 new findings could be applied to using the saliva for early cancer detection, Slomovitz suggested, which may help identify the disease even in pre-cancer states.

"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," he said. 

"These results will build a foundation for future research. However, we are not ready to incorporate this into clinical practice."

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Fox News senior medical analyst Dr. Marc Siegel also weighed in separately on the study, noting that awareness around the importance of the gut microbiome on overall health has been growing.

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"There is a correlation between the bacteria found in the gut and neurogenerative disease and increased cancer risk," he told Fox News Digital. 

"It is very important that we work toward a healthy microbiome in the gut to decrease the risk of inflammation and cancer."