MYC and neuroblastoma: Other studies using extracellular matrix secreted by trisomy 21 fibroblasts revealed a reduction in neuroblastoma cell density when non-hyperaggressive neuroblastoma cell lines (i.e., SK-N-SH and SK-N-As) were used, but not when the highly MYC-amplified IGR-N-91 neuroblastoma cell line was tested (Satgé et al., 2008).