ABSTRACT
ABSTRACT DNA methylation is an important regulator of gene expression and plays an essential role in maintaining cellular function. Its role in carcinogenesis has been a topic of considerable interest in recent years. Changes in DNA methylation patterns may contribute to the development of cancer in general and breast cancer in particular. Aberrant global methylation of DNA is frequently found in tumor cells. Global hypomethylation can result in chromosome instability, and hypermethylation has been associated with the inactivation of tumor suppressor genes. Several studies suggest that part of the cancerprotective effects associated with several bioactive components may involve modications of the DNA methylation prole. Dietary factors that are involved in one-carbon metabolism provide the most compelling evidence supporting an interaction of nutrients and DNA methylation because these factors inuence the supply of methyl groups and therefore the biochemical pathways of methylation processes. These nutrients include folate, vitamin B12, vitamin B6, methionine, and choline. This chapter examines alterations in DNA methylation in breast cancer, the effects on gene expression, and the role of nutrients in DNA methylation in the treatment of breast cancer.
