Apart from MYCN amplification, both MYC and MYCN are found upregulated in NB, either by amplification of enhancer elements or by chromosomal translocations leading to enhancer hijacking, but never together.41 Interestingly, several missense mutations of MYCN and MYCN opposite strand (MYCNOS) have also been observed in patients with NB (St Jude PeCan database).42 This evidence concerns the gene MYCN and neuroblastoma.