Researchers looking for reasons that the rates of colorectal cancer in young people are rising quickly may have found one—a discovery that an outside scientist says could provide "a critical piece of the puzzle." The study, published Wednesday in Nature, points to the gut toxin colibactin, NBC News reports. Recent studies have shown the toxin can cause DNA damage to colon cells that can lead to cancer. That damage is especially apparent in younger people, the University of California San Diego study says. The American Cancer Society reported two years ago that diagnoses of colorectal cancer in people under 55 had doubled between 1995 and 2019.
The team sequenced the DNA of colorectal cancer tumors from 981 patients in 11 countries and found that DNA mutations related to colibactin were 3.3 times more common in patients under 40 than patients over 70. About half of the early-onset colorectal cancers in people younger than 40 "carried the distinctive signature of colibactin exposure," said professor Ludmil Alexandrov. He added, per the Guardian, "We think what we're seeing is an infection in early life that subsequently increases one's risk for developing colorectal cancer in the future." Colibactin is produced by harmful gut bacteria including particular strains of E.coli, Klebsiella pneumoniae, and Citrobacter koseri, per NBC.
Obesity, junk food, and physical inactivity have been cited as possible causes of the disease. The new information, though not conclusive, could help the battle against the disease, said an expert not involved in the study. "It may be a critical piece of the puzzle," said Christopher Johnston of MD Anderson Cancer Center in Texas. (More colon cancer stories.)
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