Oral Microbiome May Predict Gastric and Colorectal Cancer, Study Finds

A groundbreaking study led by Seoul University indicates that the bacteria residing in the mouth may hold the key to detecting gastric and colorectal cancer at their earliest stages. Researchers analyzed oral and fecal samples from 507 volunteers, including healthy individuals, those with metabolic disorders, and patients diagnosed with gastric or colorectal cancer.

The study developed a "mouth-feces index" (MF) using genetic sequencing to measure the presence of identical microbial sequence variants in both oral and fecal samples. This index was significantly elevated in patients with gastric or colorectal cancer, but not in those with metabolic disorders. The association remained strong even after accounting for factors like alcohol consumption, exercise, and body mass index.

"The presence of bacteria associated with the oral cavity in the intestines of cancer patients was not entirely unexpected," stated researcher Sun Ha Jee from Yonsei University. However, the team was surprised by the variation in the signal across different disease groups and the extent to which it could be detected solely from oral samples.

Comparing the oral microbial signatures with standard fecal occult blood tests for colorectal cancer screening, the study found higher sensitivity in oral rinse samples. The researchers plan further prospective studies to validate these findings and explore the causal relationship between oral bacteria and gastrointestinal cancer.

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The presence of bacteria associated with the oral cavity in the intestines of cancer patients was not entirely unexpected.