An overview of epigenetic mechanisms in health and disease

Epigenetic modifications are emerging as key players in not only the regulation of normal genomic expression patterns, but also their role in disease progression due to their deregulation. An irregular change in DNA methylation, either through aberrant hypermethylation or hypomethylation, may have serious consequences relating to carcinogenesis by potentiating or preventing gene functions. Conversely, the reversal of abnormal hypermethylation has been aided by the advent of DNMT inhibitors to restore tumour suppressor gene function. In addition, the field of histone post-translational modifications (PTMs) is expanding. The best characterised and seemingly most involved in pathogenesis remain acetylation and methylation of amino acid residues within N-terminal tails. As the complexity of the epigenetic language becomes more apparent, it has been found that there is significant crosstalk between modifications, including DNA methylation and histone PTMs. Great promise lies in the development of histone deacetylase inhibiting compounds, which initiate a vast number of effects normalising or eradicating tumour cells.