As we have discussed previously, DNMT inhibitors, inlcuding azacitidine and decitabine, as well as HDAC inhibitors, such as depsipeptide, phenylbutyrate, valproic acid and suberoylanilide hydroxamic acid, have been widely used for cancer treatment in both experimental studies and clinical trials (Table 3). The gene discussed is HDAC9; the disease is cancer.