HDAC9 and plasma cell myeloma: Currently, there are four FDA-approved HDAC inhibitors: Vorinostat (SAHA) and Istodax (romidepsin) have been approved for the treatment of cutaneous T-cell lymphoma (CTCL) in 2006 and 2009, respectively; Beleodap has been approved for the treatment of peripheral T-cell lymphomas (PTCL) in 2014; and Panobinostat has been approved for the treatment of patients with multiple myeloma (MM) in 2015 (55).