The relationship between gut bacteria and colon cancer has become a significant area of research, as scientists seek to understand how changes in the gut microbiome might influence the development of precancerous colon polyps and their progression to cancer. A recent study published in the journal Cell Host & Microbe highlights the role of certain gut bacteria in increasing the chances that colon polyps will become cancerous. This research, led by William DePaolo, associate professor at the University of Washington School of Medicine, sheds light on how specific bacteria, such as non-enterotoxigenic Bacteroides fragilis, are more prominent in patients with colon polyps compared to those without the polyps.
Colorectal cancer is amongst the biggest health concerns, ranking as the third leading cause of cancer in the United States, with its incidence rising among young adults. Nearly all colorectal cancers originate from precancerous polyps, making early discovery and intervention important for reducing cancer rates. The gut microbiome, composed of trillions of microorganisms living in the gastrointestinal tract, plays an imperative role in health and disease.
The Role of Bacteroides fragilis
DePaolo’s research focused on identifying bacteria present in higher levels near colon polyps compared to polyp-free areas. The study involved 40 patients aged 50 to 75, with 60% being women, who underwent routine colonoscopies and biopsies near the polyps. The findings revealed that Bacteroides fragilis, a common gut bacteria, was higher in mucosal biopsies of patients with polyps. Moreover, the study established a correlation between the amount of B. fragilis and the inflammation of small polyps.
Interestingly, the B. fragilis from patients with polyps differed in its ability to induce inflammation compared to B. fragilis from polyp-free individuals. This suggests that even normally healthy bacteria can adapt and contribute to inflammation in environments where metabolic and inflammatory changes occur. This adaptation could potentially push a polyp toward cancer.