HDAC9 and primary cutaneous T-cell non-Hodgkin lymphoma: The 5 currently FDA-approved HDAC inhibitors are vorinostat (SAHA) for cutaneous T-cell lymphoma, romidepsin for cutaneous/peripheral T-cell lymphoma, belinostat for peripheral T-cell lymphoma, panobinostat for multiple myeloma, and valproic acid (VPA) for epilepsy, bipolar disorder, and migraine (Eckschlager et al., 2017; Verma and Kumar, 2018).