Patients had HRNB if they were at least 12 months of age with INSS stage 4 neuroblastoma (primary tumor with dissemination to the distant lymph nodes, bone, bone marrow, liver, skin and/or other organs, except as defined for 4S), or <12 months of age with INSS stage 4 disease and MYCN amplification [4,18]. This evidence concerns the gene MYCN and neuroblastoma.