HDAC9 and nasopharyngeal carcinoma: Hui KF, et al. reported that enhanced histone acetylation was observed after treatment with bortezomib/ class I HDAC inhibitor, romidepsin and could also be reduced upon coincubation of the drug combination with either pan-caspase inhibitor, Z-VAD-FMK or ROS scavenger, N-acetylcysteine (NAC), suggesting that the enhanced histone acetylation was ROS- and caspase-dependent in nasopharyngeal carcinoma (NPC) cells [37, 38].