Pharmaco-epigenomics: On the road of translation medicine

Epigenomics refers to the study of genome-wide changes in epigenetic mechanisms including DNA methylation, histone modifications and non-coding RNAs expression. The alterations in normal DNA methylation and histone acetylation/deacetylation patterns lead to deregulated transcription and chromatin organization resulting in altered gene expression profiles that facilitates tumor development and progression. In consequence, novel therapeutic strategies aimed at reversing aberrant epigenetic marks in cancer cells have been developed and used in recent molecular studies and clinical trials. Pharmaco-epigenomics is a research area, which refers to the study of epigenome changes in cancer development and how chemotherapeutic agents can reverse these aberrant epigenetic marks by targeting the epigenetic machinery. Besides, the effects of genome-wide polymorphisms in populations leading to variations in drug response are also study subject of pharmaco-epigenomics and are being studied extensively in cancer. Recent findings showed that drug response could be largely influenced by the presence of aberrant epigenetic marks of the whole genome. This implies that biological pathways and cellular processes are under the impact of epigenome status. However, data about the relationship between drug response and the epigenomic variations is still scarce mainly because the epigenome is highly variable between individuals. The present chapter reviewed the advances on the epigenetics changes mainly DNA methylation and histones modifications on cervical and breast human cancers. A special emphasis in how they could be used as targets for the development and use of novel drugs in cancer therapy is delineated.