Duke-NUS: Cancer Mutations Caused by Bacterial Toxin Preventable
Colibactin, a toxin produced by bacteria that often live in the gut, is linked to some cancer mutations.
Scientists from Duke-NUS Medical School in Singapore have found DNA mutations in some cancers that link them to a bacterial toxin called colibactin. Their findings, published in the journals Gastroenterology and Genome Research, improve understanding of how some cancers develop and could help in their prevention, according to a press release issued by the medical school.
Studying DNA mutations in cancers can help clarify how cancers develop and what makes cancer cells different from normal, healthy cells. The team of scientists from Duke-NUS’ Cancer and Stem Cell Biology (CSCB) program, specifically wanted to look more closely at Asian cancers to expand the list of 65 currently known mutation patterns found in cancers. Scientists expect there are still some rare mutation patterns that have yet to be discovered.
The researchers examined 872 colorectal lesions from 201 patients with unexplained, non-inherited polyposis. This condition involves the formation of intestinal polyps that can predispose people to cancer. It is usually caused by a mutation in the adenomatous polyposis coli (APC) gene. This gene is critical for several cellular processes and acts as a tumor suppressor by preventing cells from growing and dividing uncontrollably. The team found that almost 20%t of the patients had tumors with mutations in the APC gene with characteristics similar to those caused by a bacterial toxin known as colibactin, suggesting the toxin’s involvement in initiating polyp formation in these individuals.
Colibactin, is produced by a specific group of Escherichia coli bacteria, which normally live in the gut. While exposure to colibactin is difficult to prevent, the research team suggests that regular brushing of teeth might have prevented the bacterial infection that appears to have triggered the cancer-causing DNA mutation in the oral cancer patient who was examined.