A new study just connected the dots between childhood and CRC risk
Key Takeaways
Industry Buzz
“Exposure to colibactin in early childhood could imprint a distinct genetic signature on the DNA of colon cells, leaving behind specific patterns of DNA mutations that were 3.3 times more common among patients with early-onset colorectal cancer.” — Authors, The ASCO Post
“What we’re really trying to do is link a child’s immune system and what can harbor [it] to be weakened a little bit—or what can strengthen it… to see if we can try to prevent this in the future.” — Joseph Salhab, MD, a gastroenterologist
Find more of your peers' perspectives and insights below.
For years, clinicians have been tracking a disturbing trend: Colorectal cancer diagnoses are rising among adults under 50. Lifestyle factors have taken much of the blame—but the data never quite added up. Now, a new study may offer a clearer lead.
The findings:
Researchers have identified a toxin called colibactin, produced by certain strains of E. coli, as a possible contributor to early-onset CRC. The study suggests that childhood exposure to colibactin leaves behind a distinct mutational signature in colon DNA—one that shows up 3.3 times more often in patients under 40 than in those over 70.[]
This signature was also more common in countries with high rates of early-onset CRC, strengthening the link between early microbial exposure and long-term cancer risk.[]
The microbiome has always been a suspect
Joseph Salhab, MD, a gastroenterologist who frequently shares clinical insights as “The Stomach Doc,” said these findings align with longstanding concerns in the GI community.
“We’ve been suspicious that alterations in gut bacteria are involved in young-onset colon cancer,” Dr. Salhab explained in a post on Instagram.
To him, colibactin is just one piece of the broader microbiome puzzle. When pathogenic bacteria overgrow—and beneficial strains are suppressed—it can disrupt immune regulation, drive inflammation, and set the stage for cancer.[]
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According to Dr. Salhab, the primary concern is when the disruption occurs. Gut–immune system development is especially sensitive in childhood, and some individuals may struggle to recover a healthy microbiome after early-life damage.[]
“Doing things early in life can hopefully not alter your gut bacteria for the worst,” he said. “Sometimes, people have a really hard time recovering their gut bacteria, and that can certainly affect it.”
Takeaways
Dr. Salhab believes this research opens new doors—not only to understanding CRC risk, but to preventing it. He suggests focusing on the relationship between gut bacteria and immune development in early life, identifying exposures that may either weaken or fortify that system.
“What we’re really trying to do,” he said, “is link a child’s immune system and what can harbor [it] to be weakened a little bit—or what can strengthen it… to see if we can try to prevent this in the future.”
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