HDAC8 and neuroblastoma: To inhibit specifically HDAC8 activity in neuroblastoma, we decided to use and compare two structurally divergent HDAC8 inhibitors, which are both reported to be selective for HDAC8: Compound 2 (Cpd2; 1-naphthohydroxamic acid13) and PCI-34051.14 For PCI-34051, two more stable variants exist: PCI-48000 and PCI-48012.