HDAC9 and neoplasm: Notably, a recent study showed that treatment of MDA-MB-231 cells with the hydroxamate HDAC inhibitor panobinostat (LBH489) induced upregulation of many anti-proliferative, tumor-suppressor, and epithelial marker genes, and strikingly, it initiated partial reversal of the epithelial-to-mesenchymal transition in MDA-MB-231 cells [56].