Is there a link between intestinal dysbiosis and colon cancer?

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Chronic bowel inflammation associated with diet generates alterations of the local microbiota. This dysbiosis could promote the onset of colorectal tumors containing Fusobacterium nucleatum.

 

Chronic bowel inflammation associated with diet is a confirmed risk factor for colorectal cancer. The decrease in the production of protective mucin and antimicrobial peptides promotes colonization of colonic mucosa by pathogenic microorganisms and exposure of intestinal cells to mutagenic metabolites. Fusobacterium nucleatum was identified among the bacteria which promote carcinogenesis. It is an invasive anaerobic species found in a subgroup of colorectal cancer, especially proximal ones. Its presence in tumor tissues could also contribute to the progression of the disease and its chemoresistance.

EDIP, a score indicative of the inflammatory risk related to diet

In this respect, a team of American researchers studied the correlation between inflammatory effect of a diet, presence of F. nucleatum and onset of colorectal cancer. They based their study on two national cohorts* including 124,433 men and women who were monitored during 28 years through questionnaires every two years. Inflammatory effects of diet were quantified based on the EDIP score (Empirical Dietary Inflammatory Pattern), calculated based on the consumption of 18 food groups. Moreover, the presence or absence of F. nucleatum in the tumor environment was detected by analyzing tissue samples of people who developed a colorectal cancer.

Link between EDIP score and Fusobacterium nucleatum

They found that 951 subjects had, in fine, F. nucleatum-positive colorectal tumors. These patients had an EDIP score 1.63 times higher and even 2.61 higher for tumors located in the proximal colon. On the contrary, no association was established between F. nucleatum-negative tumors and EDIP score. Consequently, diets likely to promote chronic intestinal inflammation that disrupts the microbiota seem to be associated to a higher risk of developing colorectal cancer containing Fusobacterium nucleatum. The researchers believe that preventive nutritional care could thus be considered not only to limit the onset of this subgroup of cancers, but also to slow their progression thanks to personalized therapeutic approaches.

 

*Nurse’s Health Study, Health Professionals Follow-up Study

 

Sources:

L. Liu, F. Tabung, X. Zhang, et al. Diets That Promote Colon Inflammation Associate With Risk of Colorectal Carcinomas That Contain Fusobacterium nucleatum. Clinical Gastroenterology and Hepatology. DOI: 10.1016/j.cgh.2018.04.030.