Therapeutic Implications of Epigenetic Signaling in Breast Cancer

Breast cancer is a heterogeneous disease and its complexity has hindered the development of efficacious treatments targeting all breast cancer subtypes. Many studies have linked the diversity of breast carcinogenesis and metastasis to aberrant epigenetic signaling and control. Here, we focus on the current state of the discipline and review the major epigenetic enzymes controlling chromatin structure and function in the context of breast cancer, including (1) DNA methyltransferases, (2) lysine methyltransferases and demethylases, (3) protein arginine methyltransferases, and (4) histone acetyltransferases and deacetylases. Moreover, therapeutic drugs targeting these epigenetic enzymes are rapidly emerging and/or undergoing clinical trials. Therefore, we discuss the pharmacological manipulation of epigenetic enzymes for breast cancer treatment and present new clinical and survival outcome analysis on epigenetic factors that have evaded analysis to date. Understanding and pharmacologically exploiting epigenetic regulation in breast cancer promises to be an essential aspect of next-generation drug development and adjuvant therapies targeting advanced disease and treatment-resistant tumors.