HDAC8 was the first human HDAC to be crystalized with bound inhibitors,13, 14, 15, 16 but it remains one of the least understood HDACs, with no known direct transcriptional target or corepressor partner.17,18 In pursuing the mechanism of action of MSP in human colon cancer cells, we identified a key role for HDAC8 in regulating BMF gene activity and Bmf-mediated apoptosis. The gene discussed is HDAC9; the disease is malignant colon neoplasm.