MYCN and neuroblastoma: While tumors with neuroblastoma-like histology and expression of the neuroblastoma SAP lineage markers Phox2B and TH developed in 6 out of 7 mice receiving BE (2)-C cells, no tumors formed following injection of the MYCN-overexpressing progenitor cells (Fig 5), indicating that overexpression of this oncogene in multipotent SAPs is not sufficient for tumorigenesis.