The genetic alterations associated with breast carcinogenesis are well known. On the contrary epigenetic alterations in hereditary breast cancer are a new field. Two epigenetic mechanisms have emerged as the most critical players in transcriptional regulation in breast cancer: the methylation of DNA and microRNA interference.
In this review we will focus on recent findings on gene silencing caused by DNA methylation and microRNA to explore the potential role of these epigenetic changes in the understanding of hereditary breast cancer. Moreover we will describe the same alterations in basal-like breast cancer and in triple-negative breast cancer, since their phenotypes have similarities with BRCA1-mutated tumors. To underline the possibility that some epigenetic alterations could also be used as potential epigenetic biomarkers of drug sensitivity or resistance, we will discuss the more common therapies in hereditary breast cancer that could also be applied to breast cancer with basal-like or triple negative phenotypes.