HDAC Inhibitors have great potential as anti-cancer agents, but their exact mechanisms of action are not completely established. Acetylation of histone induces gene expression by altering chromatin activity; acetylation of non-histone proteins affects a variety of physiological pathways including cell growth, chromatin remodeling, DNA replication and repair, cytoskeletal reorganization, autophagy, angiogenesis, and protein chaperone activity.