Epigenetic Regulation of Breast Cancer

Abstract

Breast cancer is a carcinoma of mammary glands, which starts off as abnormal proliferation of ductal cells. This could, then, become either benign tumours or metastatic carcinomas. It is one of the most common causes of deaths because of cancer, and is one of the most common types of cancer in women in the whole world. India along with the US and China accounts for one-third of the breast cancer burden. The breast cancer carcinogenesis is attributed to epigenetics, which is the study of the reversible changes in the phenotype without any change in the DNA sequence. Genes, which are concerned with proliferation, anti-apoptosis, invasion, and metastasis, have been seen undergoing epigenetic changes in breast cancer. Cancer can be caused either by global hypomethylation (causing activation of oncogenes and leading to chromosomal instability) or by locus-specific hypermethylation (causing repression of gene expression and genetic instability due to inactivation of DNA repair genes). Other epigenetic mechanisms involved in carcinogenesis are histone modification and nucleosomal remodeling.