Gut microbiota and obesity-related gastrointestinal cancer: a focus on epigenetics

Changes in DNA methylation and histone modifications are important in the development of many diseases including cancer. These epigenetic alterations drive the formation of cancer by altering the expression of critical genes such as those controlling proliferation, survival and cell migration. The microorganisms that colonise the gastrointestinal tract (gut microbiota) are potentially a source of localised microbial-induced epigenetic change. Recent evidence shows that obesity is associated with dramatic differences in the composition of gut microbiota when compared with normal-weight individuals. This review explores the evidence for microbial-induced epigenetic changes and hypothesizes that this may contribute to the pathogenesis of obesity-related colorectal cancer.