Introduction: diet, epigenetic events and cancer prevention

Epigenetics is defined as heritable changes in gene expression not associated with alterations in DNA sequence. NA methylation, histone modifications, chromatin remodeling factors, and noncoding regulatory RNAs are all known to be involved in epigenetic regulation of chromatin structure and gene activity. These epigenetic regulatory processes are considered critical components of normal development in cellular differentiation, organogenesis, and aging. Additionally, there is mounting evidence that epigenetic abnormalities are causative factors in several diseases, including cancer. Evidence also continues to surface for constituents in food and dietary supplements to influence gene expression, as well as an individual's risk of developing some cancers. Since epigenetic regulatory processes may be susceptible to changes caused by environmental factors, they offer potential mechanistic explanations for how diet may modify cancer risk and tumor behavior.