Intestinal microbiota, chronic inflammation, and colorectal cancer

dition to genetic susceptibility, epigenetic mechanisms are also involved in colorectal carcinogenesis.For example, the epigenome of CRC usually has hundreds to thousands of abnormally methylated genes, and a subset of these are thought to initiate the development of CRC. 7 In additional to genetic and epigenetic factors, the intestinal microbiota is increasingly recognized as a confounding factor in the development of CRC.Finally, other environmental factors, such as diet, also play an important role in the development of CRC. 8 For example, high dietary fiber intake is associated with a reduced risk of CRC, while high intake of red meat and processed meat is associated with an increased risk of CRC.9,10 The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), reported the risk of excessive consumption of red meat and processed meat.11 A study on colon cancer risk in Japanese immigrants showed progressive changes in the incidence of colon cancer among Japanese after migrating to Hawaii.12 Such evidence supports a strong relationship between diet and the development of CRC.Recently, interest in the intestinal microbiota as an environmental factor for CRC has increased, because diet also influences the composition of the intestinal microbiota.The