Co-amplification of ODC1, a gene located 5.5 Mb upstream of MYCN and co-amplified in 9% (21/240) of MYCN-amplified neuroblastomas (Fig. 2c), defined an ultra-high-risk genetic subgroup of MYCN-amplified neuroblastoma (hazard ratio (HR) 2.3 (1.4–3.7), log-rank test P = 0.001; Fig. 6b). This evidence concerns the gene ODC1 and neuroblastoma.