Gut microbiota and colorectal cancer: insights into pathogenesis for novel therapeutic strategies.

Colorectal cancer (CRC), as a leading cause of cancer-related death, is triggered by the complex interplay of host genetics and environmental factors. Mounting evidence has shed light on the association of the gut microbiota dysbiosis with CRC. In CRC experimental models, certain gut microbial strains have been shown to inhibit or attenuate immune responses, indicating that specific species among intestinal commensal bacteria may play either a pathogenic or a protective role in the development of CRC. Oral intake of probiotics/prebiotics can therefore serve as a therapeutic approach for CRC treatment. Microbiota studies in cancer, however, are still at the early stage, lack of quantitative data for clinic application. Fortunately, sequencing-based technologies are a boon to further investigation on the association of the intestinal bacterial flora and human diseases. This review considers the evidence for the role of the gut microbiota in CRC development and progression, responsiveness to immune system, and the related therapeutic applications of probiotics/prebiotics.