**2. Epigenetics**

Epigenetics is the study of heritable changes in phenotype or gene expression caused by mechanisms other than changes in DNA sequence. The molecular mechanisms of epigenetic inheritance and its relationship with the expression of chromatin include three interrelated processes, namely DNA methylation, genomic imprinting and histone modifications (Kouzarides, 2007). Through small chemical molecules called methyl groups, which bind covalently with DNA or histones, the epigenetic processes improve the ability of genome to store and transmit biological information beyond the known structure and sequence of genetic material.

In recent years we have faced a new paradigm, a view more focused on the cell and on the search for information layers outside of the cell nucleus and even of the DNA as the center for information of the cell. These layers of epigenetic information transcend embryogenesis and cancer development processes, as follows.
