A rationally designed, orally available, Class 1-selective, small molecule, 2-aminobenzamide HDAC inhibitor with potential antineoplastic activity. Mocetinostat binds to and inhibits Class 1 isoforms of HDAC, specifically HDAC 1, 2 and 3, which may result in epigenetic changes in tumor cells and so tumor cell death; although the exact mechanism has yet to be defined, tumor cell death may occur through the induction of apoptosis, differentiation, cell cycle arrest, inhibition of DNA repair, upregulation of tumor suppressors, down regulation of growth factors, oxidative stress, and autophagy, among others. Overexpression of Class I HDACs 1, 2 and 3 has been found in many tumors and has been correlated with a poor prognosis. A substance being studied in the treatment of several types of cancer. It blocks enzymes needed for cell division and may kill cancer cells. It is a type of histone deacetylase (HDAC) inhibitor. Also called MGCD0103.