The Association of Microbiome Dysbiosis With Colorectal Cancer

Abstract

Many studies have been conducted to identify the causative organisms in colorectal cancer (CRC) and compare the microbiota of healthy individuals and those with CRC. The pathways by which the microbiota promotes CRC development are not yet fully understood. The hypothesized mechanisms include damage to the DNA, production of carcinogenic metabolites, and promotion of chronic inflammation. In a state of dysbiosis, the gut loses protective bacteria and is enriched with pathogenic and cancer-promoting bacteria, which promotes functions associated with cancer such as angiogenesis, loss of apoptosis, and cell proliferation. We have established a strong link between microbiota dysbiosis and certain species of bacteria and even viruses involved in tumorigenesis. In this review, we look at some of the major identified species and how they are related to CRC. Future research should include and even focus on mycobiome and virome on CRC development. Due to the diversity of the gut microbiome, there is a high possibility that the gain and loss of bacteria and their metabolic functions lead to CRC.

Keywords: bacterial dysbiosis; cancer genomics; colon cancer prevention; colorectal cancer; gut microbiota; microbiome.

Figure 1. Pathophysiology of Bacteroides fragilis toxin resulting in colorectal cancer