Epigenetic Regulation in Breast Cancer.

Aberrant epigenetic alteration has been associated with development of various cancers, including breast cancer. Since epigenetic modifications such as DNA methylation and histone modification are reversible, epigenetic enzymes, including histone modifying enzymes and DNA methyltransferases, emerge as attractive targets for cancer therapy. Although epi-drugs targeting histone deacetylation or DNA methylation have received FDA approval for cancer therapy, a very modest anti-tumor activity has been observed with monotherapy in clinical studies of breast cancer. To improve efficacy of epi-drugs in breast cancer, combination of epi-drugs with other therapies currently has been investigated. Additionally, basic researches to elucidate molecular causes of cancer should be extensively and intensively conducted in order to find novel epigenetic druggable targets. In this chapter, we summarize how epigenetic regulation affects the development of breast cancer and how to control cancer phenotype by modulating abnormal epigenetic modifications, and then suggest future research directions in epigenetics for breast cancer treatment.