HDAC9 and primary cutaneous T-cell non-Hodgkin lymphoma: Four pan-HDAC inhibitors—Vorinostat (SAHA) for relapsed and refractory cutaneous T-cell lymphoma (CTCL), Belinostat for peripheral T-cell lymphoma (PTCL), Romidepsin for CTCL/PTCL and Panobinostat for multiple myeloma – are approved for market use as treatment options by the FDA and/or EMA [18].