In this study, we treated AML cells in vitro with a novel benzamide chemical class of HDAC inhibitor chidamide (Epidaza, CS055) that selectively inhibited HDAC1, 2, 3 and 10, which is currently in phase II clinic developments against relapsed and refractory peripheral T cell lymphomas and non-small cell lung carcinomas in China and US [18], [31]. Here, HDAC9 is linked to acute myeloid leukemia.