The findings not only suggest that the composition of the microbiome can predict the presence of precancerous colon lesions, but that it might, in itself, be functionally related to their development.
Both adenoma and carcinoma were associated with a "dramatic loss" of strains of Clostridium, Bacterioides, and Lachnospiraceae. "Each of these bacterial taxa is a well-known producer of short-chain fatty acids in the colon. The fatty acids are important microbial metabolites that supply nutrients to colonocytes and help maintain epithelial health and homeostasis," Dr. Zackular and his associates said.
One of these fatty acids, butyrate, displays antitumorigenic properties, including inhibiting tumor cell proliferation, initiating tumor cell apoptosis, and mediating T-regulatory cell homeostasis.
"Loss of these important bacterial populations in concert with an enrichment of pathogenic populations likely plays a synergistic role in potentiating tumorigenesis," they wrote.
The study was funded by the National Institutes of Health. Neither Dr. Zackular nor his colleagues had any financial disclosures.