20 also observed no appreciable impact of IFNα as a monotherapy on growth and attachment rate to endothelium in neuroblastoma cells, but profound effects when combined with VPA. Kuljaca et al. 21 have also reported co-operative cytotoxic and antiangiogenic potentiation of HDAC-inhibition with IFNα in a range of cancer cell lines including DU-145 and LNCaP cells, whereas IFNα alone was not effective. This evidence concerns the gene HDAC9 and neuroblastoma.