Recent studies have found an association between colorectal cancer (CRC) and intestinal microbiota. A possible mechanism by which the microbiota can influence the physiology of the host is through the expression of the gene in the host cells. MicroRNAs (miRNAs) are small non-coding RNA molecules that can regulate gene expression and play an important role in the development of cancer. This study has investigated the link between the intestinal microbiota and the expression of miRNA in CRC. We found that dozens of miRNAs are differentially regulated in tumors of CRC and normal adjacent colon and that these miRNAs correlate with the abundance of microbes in the tumor microenvironment.

This is the first study that characterizes the relationships between intestinal microbial communities and the expression of miRNA in colorectal cancer (CRC) tissues in humans. Experimental validations are needed to investigate the correlations and their functional implications. According to the authors, “our data show a network of interconnection between the expression of miRNA and the composition of the microbiome and support the role of miRNAs in the mediation of host-microbiome interactions.” Follow-up studies using model systems are justified for evaluate the causal role of individual microbes and miRNAs in CRC. “