Study: Toxin-producing E. coli strain could contribute to cancer

E. coli

New findings suggest toxin-producing microbes in the gut could lead to cancer, according to research published in Science.

Mice with inflammatory bowel disease have more of these toxin-producing bacteria, which could lead to certain cancers. Humans with the same cancer also have been found to have these bacteria.

The bacteria at the root of it is a strain of E. coli, a common microbe found in the gut that typically is harmless. However, some strains of E. coli, such as those that produce Shiga toxin, can cause severe foodborne illness.

Certain toxin-producing strains of E. coli can cause cancer when the gut is inflamed, according to the research. People with inflammatory bowel disease can develop colorectal cancer at much higher rates than those without stomach problems, according to an article on

The researchers think this increase in cancer rates stems from DNA-damaging molecules produced by immune cells in the gut along with the bacteria.

Researchers found mice with inflammatory bowel disease developed a different “gut microbiome” than normal mice. This different environment contained much higher proportions of E. coli than the normal mice, including E. coli NC101, which is linked to a severe type of bowel disease in mice. E. coli NC101 also produces colibactin, a DNA-damaging protein.

One hypothesis is inflammation of the gut allows colibactin-producing bacteria to flourish while the cells lining the gut weaken, which makes them more likely to incur damage to their DNA. It’s this damage that is thought to cause cancer, according to the study.

To read the full article from, click here.

To read the study’s abstract, click here.

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