A bacterial toxin called colibactin can cause DNA damage in children, and this damage can be found as one of the earliest genetic changes in tumors that develop in the colon later in life.

DNA damage from certain bacteria in early childhood may lead to colorectal cancer that appears later in adulthood.

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.

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.

Colorectal cancers with colibactin-related DNA damage patterns show the same levels of overall mutations and known cancer-causing gene changes as other colorectal cancers, suggesting colibactin causes cancer through a different biological mechanism.

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.