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.

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.

Certain strains of E. coli that produce a toxin called colibactin are linked to a specific pattern of DNA damage found in colorectal tumors. This DNA damage pattern is more commonly found in tumors from people diagnosed with colorectal cancer before age 55 compared to those diagnosed at age 59 or older.

In colorectal cancers infected with bacteria that produce colibactin, a specific pattern of DNA damage caused by this toxin accounts for about one-quarter of harmful mutations in the APC gene, which is known to initiate tumor development.

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.

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.