The HDAC-mediated gene regulation process is dysregulated and promotes oncogenic phenotype of cancer cells, thus the inhibition of HDAC with chemical inhibitors (HDACi) is under active preclinical and clinical investigation with several products, such as vorinostat (suberanilohydroxamic acid) and panobinostat (hydroxamic acid), approved by the US Food and Drug Administration [2,3,4,5]. The gene discussed is HDAC9; the disease is cancer.