Cotreatment with the Brd4 inhibitor JQ1 and the HDAC inhibitor panobinostat synergistically induced apoptosis of human acute myelogenous leukemia (AML) blast progenitor cells (BPC) through attenuation of c-Myc and Bcl-2 expression, while increasing p21 and Bim expression [218]. Here, HDAC9 is linked to acute myeloid leukemia.