Furthermore, we discuss possible mechanisms whereby these histone/protein deacetylases facilitate the switch between DNA double-strand break (DSB) repair pathways, how SIRTs play a central role in the crosstalk between DNA repair and cell death pathways due to their dependence on NAD<sup>+</sup>, and the influence of small molecule HDAC inhibitors (HDACi) on cancer cell resistance to genotoxin based therapies.
Epigenetic dysregulation is a hallmark of cancer executed by a number of complex processes the most important of which converge on DNA methylation and histone protein modifications.