MYCN and neuroblastoma: Strikingly, secretion of IFNα, which is a cytokine specifically produced by PDC upon R848 or CpG-A activation, was significantly increased when immune cells were in contact with the MYCN-nonamplified neuroblastoma cell lines AS and SH, suggesting that these cell lines, but not the MYCN-amplified cell lines, were able to create a microenvironment favoring plasmacytoid DC activation.