A recent phase 1 trial of MS-275, a benzamide derivative with potent HDAC inhibition and antitumor activity in preclinical models, was used in patients with advanced myeloid leukemias and showed no response by classical criteria, but suggested a potentially better clinical outcome if tested in a cohort of patients with less-advanced disease [46]. This evidence concerns the gene HDAC9 and myeloid leukemia.