MicroRNAs and inflammation in the pathogenesis and progression of colon cancer.

There is a strong connection between inflammation, altered microRNA (miRNA) expression and colon cancer. Longstanding inflammatory bowel diseases-related colitis leads to increased risk for the development of colorectal cancer (CRC), while sporadic CRC is in part driven by the inflammatory microenvironment. This supports a causative role for inflammation in colon carcinogenesis. miRNAs are a class of small noncoding RNAs that have recently emerged as key players in both inflammation and cancer. Some miRNAs act as inflammatory mediators, others can act as either oncogenes or tumor suppressors depending on the cellular environment in which they are expressed. In particular, miR-21 is an oncogenic miRNA that has been implicated as an inflammatory mediator and may promote inflammation-associated colon carcinogenesis. miRNAs have potential as biomarkers and therapeutic targets in CRC. They are currently being evaluated as early detection biomarkers and prognostic classifiers. Polymorphisms in miRNAs and miRNA-binding sites may alter one's risk of CRC. This review will focus on the role of inflammation and miRNAs in colon carcinogenesis and discuss the potential for miRNAs and inflammatory genes to be used as biomarkers and therapeutic targets of CRC.