Colorectal cancer is increasing among young people, this bacteria could be the cause

A worrying increase in colorectal cancers has been observed among young people around the world, as in France, but the reasons for this phenomenon are currently unknown.

More and more young people are being affected by cancer, particularly colorectal cancer. Between 2000 and 2020, the number of cases increased by nearly 1.5% among those under 40 in France, according to the National Cancer Institute . Several avenues are being explored: the increase in obesity and a sedentary lifestyle, the environment, diet, antibiotics, etc.

In investigating the causes of this increase, American researchers claim in a press release to have "identified a potential culprit behind the alarming increase in early-onset colorectal cancers." It's a toxin produced by a bacterium called colibactin. Exposure to this toxin during childhood could be the cause of the "epidemic of colorectal cancer in young people," according to researchers from the University of San Diego.

Colibactin is "produced by certain strains of Escherichia coli that reside in the colon and rectum." This toxin is known to scientists for its ability to alter DNA. Specifically, the researchers analyzed colorectal cancer DNA from patients in different countries. They observed that DNA changes caused by colibactin were "3.3 times more common" in early-onset cancers than those diagnosed after age 70. They were also "particularly prevalent in countries with a high incidence of early-onset cases."

Colibactin may also cause genetic mutations "that directly promote the development of cancer." If these mutations occur before the age of 10, they could promote the onset of colorectal cancer much earlier than average. The researchers explain that "colibactin-producing bacteria can silently colonize children's colons, initiate changes in their DNA, and potentially set the stage for colorectal cancer long before symptoms appear."

One of the study's authors, Professor Ludmil Alexandrov, believes that this discovery "changes the way we think about cancer. It may not just be about what happens in adulthood - cancer could be influenced by events early in life, perhaps even in the first few years."

Further research is needed to confirm this hypothesis and provide more details. The researchers will attempt to answer many of the questions raised by their research published in Nature . "How are children exposed to colibactin-producing bacteria, and what can be done to prevent or mitigate this exposure? Are certain environments, diets, or lifestyles more conducive to colibactin production?"