[gdpawel]

Scientists can only explain a small proportion of a person's predisposition to complex diseases based on genetics alone. Epigenetics could provide the missing link. And the distinction between epigenetic changes and genetic changes is that epigenetic changes appear to be reversible.

Epigenetics is a whole new science with important implications for the treatment of disease, most notably cancer. Epigenetics is the study of molecular modifications which sit on top of the DNA in our cells, in effect switching our genes on and off, telling our cells how they should behave.

Scientists are now realizing that if those epigenetic markings are disrupted, causing a gene to become incorrectly active or silent, a healthy cell could become diseased. Research is beginning to uncover the mechanisms behind these switches and the circumstances under which changes occur.

We have hundreds of genes which, when working properly, keep healthy cells in check. These can be disrupted by damage directly to their DNA, but it's now been realized that epigenetic changes could also be responsible. A common epigenetic change in cancers is DNA methylation, which silences genes.

Almost every cancer cell has problems with the epigenetic programming, so an increasing focus of research has been to find drugs which can remove these chemical changes. Rather than killing cancer cells, decitabine and azacitidine remove the aberrant methylation, reactivating genes which had been silenced.