Could Bacteria Play a Role in Colon Cancer?

Bacterial 'bunches' were prevalent on colon polyps, cancers, study found

By Robert Preidt

Friday, December 19, 2014

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FRIDAY, Dec. 19, 2014 (HealthDay News) -- Dense bunches of bacteria called biofilms can be found on most colon polyps and cancers, a new study finds.

The researchers said these biofilms were especially prevalent on the right side of the colon.

The presence of these biofilms may represent an increased likelihood of colon cancer and could offer a new way to predict a person's risk for the disease, the researchers said.

Like tooth plaque and slime on pond stones, these biofilms may coat the mucus layer of cells lining the colon, according to background information from the study. There, the biofilms may cause inflammation and some noncancerous bowel diseases, said Dr. Cynthia Sears, professor of medicine and oncology at the Johns Hopkins University School of Medicine and Bloomberg School of Public Health.

The researchers examined healthy and cancerous tissue collected during biopsies on almost 120 people. Biofilms were present on 89 percent of tumors removed from the right colon, according to the researchers.

Biofilms were found on only 12 percent of tumors removed from the left side of the colon. The reasons for the difference between the right and left side of the colon are unknown, the researchers said.

The risk of developing colon cancer may be five times higher in people with biofilms on the right side of the colon, compared to those with no biofilms, said the authors of the study.

"What was so striking was that these biofilm-positive samples cluster so dramatically in the right colon. In fact, it's virtually a universal feature of tumors that appear in that section of the colon, although we don't understand why," Sears said in a Hopkins news release.

It may be possible to develop a noninvasive test to detect these biofilms and predict a person's risk of developing colon cancer. Most of these cancers develop over five to 10 years "and it's a disease that's curable if you diagnose it early," Sears said.

Colonoscopies are currently the "gold standard" in detecting colon cancer. But only about 60 percent of Americans get them, according to the researchers. And colonoscopies often aren't available in resource-poor countries, they noted.

The study was published online recently in the journal Proceedings of the National Academy of Sciences.

SOURCE: Johns Hopkins Medicine, news release, Dec. 16, 2014

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