MYCN and neuroblastoma: To investigate the therapeutic potential of the hTERT-driven oncolytic adenoviruses against MYCN-amplified NB cells, the viability of NB cells was evaluated on day 3 after virus infection using an sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)2H-tetrazolium-5-carboxanilide) assay.