HDAC9 and neuroblastoma: Our previous investigations unraveled specific and non-redundant oncogenic functions of HDAC2/3/5/8/10 in neuroblastoma pathophysiology.19, 20, 23, 73, 74 The clinical application of pan-HDAC inhibitors showed dose-limiting toxicities, which is not surprising considering the central role of HDACs in modulating chromatin structure and cytoplasmic processes such as autophagy.