Epigenetics

In the past, the term epigenetics was used to describe all biological phenomena that do not follow normal genetic rules. Currently, it is generally accepted that epigenetics refers to the heritable modifications of the genome that do not involve changes in the primary DNA sequence. Important epigenetic events include DNA methylation, covalent post-transcriptional histone modifications, RNA-mediated silencing, and nucleosome remodeling. These epigenetic inheritances take place in the chromatin-mediated control of gene expression and are responsible for chromatin structure stability, genome integrity, modulation of the expression of tissue-specific genes, and embryonic development, which are essential mechanisms allowing the stable propagation of gene activity states from one generation of cells to the next. Importantly, during the past years, epigenetic events have emerged to be considered as key mechanisms in the regulation of critical biological processes and in the development of human diseases. From this point of view, the importance of epigenetic events in the control of both normal cellular processes and altered events associated with diseases has led to epigenetics being considered as a new frontier in cancer research.