HDAC9 and primary cutaneous T-cell non-Hodgkin lymphoma: FK228 (Romidepsin, FR901228), also known as depsipeptide, is an HDAC inhibitor that is isolated from a fermentation product of violaceina8, 9 and was approved by the U.S. Food and Drug Administration for the treatment of cutaneous T-cell lymphoma (CTCL) in 2009 and peripheral T-cell lymphoma (PTCL) in 2011.