MYCN and neuroblastoma: NB patients were also stratified in two groups according to MYCN amplification, the lower risk group consisting of non‐MYCN‐amplified and localized tumors (stages‐1, ‐2, and ‐3) and metastatic forms for children under 18 months (stages‐4 and 4S) (Matthay et al, 2016).