HDAC9 and hematologic disorder: Quit a few investigational HDAC inhibitors have already reached the Phase 3 stage for solid cancer treatment, and several HDAC inhibitors such as Vorinostat, Romidepsin, Belinostat, and Panobinostat have already been approved by the U.S. FDA for the treatment of patients with hematological malignancies [98,118,119,120].