HDAC9 and leukemia: However, so far, the use of FDA-approved epigenetic drugs is mostly limited to haematological malignancies, consistent with the increasing epigenetic profiling of cancer: Vorinostat (HDAC inhibitor) for cutaneous T-cell lymphoma, Panobinostat (HDAC inhibitor) for multiple myeloma, and 5-azacytidine and decitabine (DNA-methyltransferase inhibitors) for certain types of leukaemia.