These HDAC inhibitors were approved by FDA for treatment of different types of lymphoid malignancies: (1) vorinostat and romidepsin for cutaneous T-cell lymphomas [82]; (2) romidepsin and belinostat for peripheral T-cell lymphomas [83]; and (3) panobinostat in combination with dexamethasone for the treatment of multiple myeloma [83, 84]. Here, HDAC9 is linked to peripheral T-cell lymphoma, not otherwise specified.