HDAC inhibitors, a class of epigenetic therapeutics, are truly pleiotropic agents that exert their anti-tumor activity through diverse mechanisms, including up-regulation of death receptors, generation of reactive oxygen species (ROS), disruption of multiple cell cycle checkpoints and DNA repair processes, down-regulation of survival-related proteins, and induction of pro-apoptotic proteins, among many others (104–106). This evidence concerns the gene HDAC9 and neoplasm.