Study: Colibactin-producing gut bacteria fuel colorectal cancer surge

Editor's Note

Research published in Nature reveals that DNA damage caused by colibactin-producing gut bacteria is far more prevalent in younger patients with colorectal cancer, NBC News reports, suggesting a key factor behind the disturbing rise in cases among people under 40. 

According to the April 23 article, researchers from the University of California San Diego sequenced tumor DNA from 981 colorectal cancer patients across 11 countries. DNA mutations linked to colibactin were found to be 3.3 times more common in patients under 40 than those over 70. Senior study author Dr. Ludmil Alexandrov stated that about half of early-onset colorectal cancers in people under 40 showed clear evidence of colibactin exposure. This finding comes as US data show colorectal cancer diagnoses in those under 55 have doubled since 1995, with rates of advanced disease in people under 50 rising by around 3% per year.

As detailed in the article, Alexandrov explained that colibactin’s DNA-damaging effects may begin in childhood, with early-life factors such as antibiotic use, increased consumption of processed foods, reduced fiber, more C-section births, less breastfeeding, and early group childcare potentially contributing to a higher abundance of colibactin-producing bacteria in young people’s guts. These changes may be shifting the balance toward early-life acquisition of these harmful microbes and setting the stage for cancer decades later.

Questions remain about individual susceptibility to colibactin’s effects and how much lifestyle patterns drive these trends, NBC reports. Other bacteria, such as Fusobacterium nucleatum and Bacteroides fragilis, may also interact with colibactin-producing strains to amplify DNA damage or aid tumor growth. Experts cited in the article say that cancer risk may reflect a combination of microbial factors.

Looking ahead, Alexandrov and colleagues plan to develop a noninvasive stool test to detect past exposure to colibactin-producing bacteria and identify people at heightened risk before cancer develops. The outlet also notes that experts are calling for new preventive strategies, including vaccines or targeted probiotics, to help eliminate these microbes and reduce cancer risk in the future.