Polyposis family : an association of bacteria makes the bed for bowel cancer

Health 2 February, 2018


Published the 02.02.2018 at 08h51


Keywords :

cancer colonpolypose familialebactéries intestinal

Through a series of experiments, a research team has identified two bacteria linked to colon cancer. Each type of bacteria is not itself bad for the health of the large intestine, but their association degrades the layer of mucus that protects it and is responsible for an inflammation of the lining of the intestine.
Christine M. Dejea and his colleagues started by analyzing samples of tissue from patients with a genetic disorder that exposes them to an increased risk of developing pre-cancerous polyps in the colon, the “familial adenomatous polyposis” (FAP). In contrast to samples of patients with polyps isolated, the samples of mucosa from patients with familial adenomatous polyposis contained colonies of bacteria in which Escherichia Coli and Bacteroides fragilis are particularly represented. A result confirmed by analysis on a larger sample of patients with familial adenomatous polyposis .

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When the researchers implanted these bacteria in an experimental model of mice with adenomatous polyposis coli, they found that mice who received only one of these 2 bacteria developed few tumors. Conversely, the mice that received the two bacterial species sets were significantly more prone to develop an invasive cancer and die.
Continuing their series of experiments, the Dr. Dejea and his team have found that Bacteroides fragilis alters the microenvironment of the gut by depleting the mucus and inducing an inflammatory response. This would allow Escherichia Coli to contaminate the wall of the intestine and create a chronic inflammation. On the basis of these results, the authors suggest that the early elimination of these bacteria from the mucosa of patients with Escherichia Coli could be more beneficial than the simple anti-inflammatory treatment that is required in this condition to reduce the risk of degeneration and cancer.

This study comes to add to the number of study that demonstrates the importance of a good balance of the intestinal flora, the intestinal microbiota “, and, therefore, to develop approach to nutrition in order to maintain this balance or to restore it.