Colibactin-producing Escherichia coli strains induce specific double-strand DNA breaks in colonic epithelial cells, resulting in mutational signatures SBS88 and ID18.

Study: Geographic and age variations in mutational processes in colorectal cancer

This study found that a type of harmful gut bacteria leaves a unique fingerprint in the DNA of colon cancer cells, especially in younger people. These fingerprints match what scientists expect from the bacteria’s toxin, so it’s strong evidence that the bacteria causes this specific DNA damage.

Study: Abstract 2796: Colibactin mutation signatures are associated with younger age of onset in colorectal cancer

This study shows that a specific type of gut bacteria produces a toxin that damages DNA in colon cells in a very specific way, leaving a fingerprint called SBS88 — exactly what the claim says.

Study: Enrichment of colibactin-associated mutational signatures in unexplained colorectal polyposis patients

This study found that people with certain rare gut bacteria produce a toxin that leaves a specific fingerprint of DNA damage in colon cells — exactly the kind of damage the claim says these bacteria cause.

Study: Surface expression of antitoxin on engineered bacteria neutralizes genotoxic colibactin in the gut

This study shows that a harmful chemical made by certain gut bacteria damages DNA, and when scientists block that chemical, the damage stops. Since this exact type of DNA damage is linked to two known cancer-related signatures, the study supports the idea that these bacteria cause those signatures.