HDAC9 and cancer: Some HDAC inhibitors have been developed for the treatment of cancers, such as apicidin, Gd-metallofullerenol nanomaterial, MS-275, M344, N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA), panobinostat, trans-3,4,5-trihydroxystilbene (resveratrol), romidepsin, S-7-oxo-7-(4-phenylthiazol-2-ylamino)-heptyl) 2-methylpropanethioate (PTACH), sodium butyrate, suberoylanilide hydroxamic acid (SAHA), TMP269, trichostatin A (TSA), valproic acid (VPA), and WJ25591, among others (Table 1) [7,15,17,18,20,21,22,23,24,25,26,27,28].