Tucidinostat, a selective HDAC inhibitor having specificity for HDAC1, HDAC2, HDAC3, and HDAC10 subtypes, has been approved for the treatment of relapsed or refractory peripheral T cell lymphoma and is under clinical development globally for various other neoplastic and non-neoplastic diseases. Here, HDAC3 is linked to peripheral T-cell lymphoma, not otherwise specified.