Colorectal tumors with specific DNA damage patterns caused by colibactin often do not contain the bacteria that produce it at the time of diagnosis, suggesting the bacteria were present earlier and have since been cleared.

48

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Evidence from Studies

Supporting (1)

48

Community contributions welcome

48

Geographic and age variations in mutational processes in colorectal cancer

Cross-Sectional Study

Human

2025 Jul

The study found that certain DNA damage patterns in colon tumors are more common in younger patients, meaning the harmful bacteria likely infected them when they were kids, even if the bacteria aren't there anymore when the tumor is found.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Geographic and age variations in mutational processes in colorectal cancer

Score: 48

DOI: 10.1038/s41586-025-09025-8

Science Topic

Are colibactin-induced DNA signatures in colorectal cancer linked to the presence of colibactin-producing bacteria at diagnosis?

Supported

We analyzed the available evidence and found that colorectal tumors with DNA damage patterns linked to colibactin often do not contain the bacteria that produce it at the time of diagnosis. This suggests the bacteria may have been present earlier, caused damage, and then been cleared by the body before the tumor was detected [1]. The evidence we’ve reviewed so far leans toward the idea that the presence of these DNA signatures does not require the bacteria to still be there when the cancer is diagnosed. Instead, the damage may be a lasting mark left behind after the bacteria are gone. We did not find any studies that contradict this pattern. This means that detecting colibactin-related DNA changes in a tumor could point to past exposure to these bacteria, even if they are no longer present. It also suggests that the timing of bacterial presence matters more than its current presence when assessing risk or damage. Our current analysis shows this pattern is consistent across the evidence we’ve reviewed, but we don’t yet know how long after infection the bacteria are cleared, or why some people’s bodies remove them while others don’t. For now, if you have colorectal cancer and your tumor shows these DNA signatures, it may mean colibactin-producing bacteria were involved earlier in the process — even if they’re not detectable today.

2 items of evidenceView full answer

Similar Assertions

Colorectal cancers diagnosed before age 40 are more likely to show specific DNA damage patterns linked to colibactin-producing bacteria than cancers diagnosed after age 70, suggesting that exposure to these bacteria earlier in life may be associated with faster development of tumors in the lower colon and rectum.

48

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92%

Colorectal cancers diagnosed before age 50 are three to four times more likely to carry a specific DNA mutation pattern linked to colibactin-producing bacteria than cancers diagnosed after age 50, indicating that exposure to these bacteria earlier in life may be linked to the increase in early-onset colorectal cancer.

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90%

DNA damage caused by the bacterial toxin colibactin is found in the earliest genetic changes in colorectal cancer, suggesting that exposure to this toxin happens early in life and helps create the initial mutations that lead to cancer.

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90%

In 11 countries, regions with higher rates of specific DNA damage patterns linked to colibactin-producing bacteria also have higher rates of colorectal cancer, suggesting that differences in exposure to these bacteria may help explain why cancer rates vary by location.

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88%

Certain strains of E. coli that produce colibactin are linked to distinct patterns of DNA damage found in colorectal tumors, particularly in younger patients, and these damage patterns are found in a portion of the mutations that drive tumor development.

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87%