Epigenetic Mechanisms in Breast Adenocarcinoma: Novel DNA Methylation Patterns

Abstract

Breast adenocarcinoma is a leading cause of death in females worldwide. A broad spectrum of genetic and epigenetic alterations has been already identified and reported in millions of examined cancerous substrates, evidence of a high-level genomic heterogeneity that characterizes these malignancies. Concerning epigenetic changes and imbalances that critically affect progression and prognosis in the corresponding patients, DNA methylation, histone modifications (acetylation), micro-RNAs (miRs) alterations and chromatin re-organization represent the main mechanisms. Referring to DNA methylation, promoter hyper-hypo methylation in critical tumour suppressor and oncogenes is implicated in normal epithelia transformation to their neoplastic and finally malignant cyto-phenotypes. The current review is focused on the different methylation patterns and mechanisms detected in breast adenocarcinoma and their impact on the corresponding groups of patient response to specific chemotherapeutic regimens and life span prognosis.

Keywords: Breast; DNA; adenocarcinoma; epigenetics; genes; methylation; review.

Figure 1. Breast carcinoma is characterized by a variety of genetic and epigenetic aspects that lead to different gene expression levels and DNA structural changes. Focused on DNA methylation activity, insertion of one or multiple new methyl groups (CH3) directly in the 5' position of cytosine residues at Cytosine-Phosphate-Guanosine dinucleotide areas (CpG islands) is promoted by specific DNA enzymes, the methyl-transferases.