HDAC inhibitors, including trichostatin A, vorinostat (suberoylanilide hydroxamic acid, SAHA), trapoxin A, and valproic acid, are effective in the treatment of lung, breast, and esophageal cancers, whereas, SAHA has been approved by the Food and Drug Administration (FDA) for the treatment of T-cell lymphoma (28–31). The gene discussed is HDAC9; the disease is T-cell non-Hodgkin lymphoma.