HDAC9 and cancer: Among HDAC inhibitors, hydroxamic acid-based vorinostat (also known as SAHA and Zolinza) suppresses the activity of all HDACs except for HDAC III and exhibits anti-cancer functions including growth arrest promotion, activation of the extrinsic and/or intrinsic apoptotic pathways, induction of autophagic cell death, ROS-induced cell death, mitotic cell death, and senescence-selectively in tumor cells.