MYCN in neuronal tumours.

MYCN is a member of the MYC family of oncogenes that encode nuclear proteins serving as transcription factors. Activation of MYC family genes, usually by genetic damage with the consequence of enhanced expression of a wild-type protein, has been found to participate in human and animal cancers. While activation of the MYC oncogene does not show an association with a particular cancer type, genetic damage involving MYCN has high preference for tumours of neuroectodermal derivation. In the vast majority of cases, the activation mechanism involves the increase of the MYCN gene dosage, either by amplification resulting in up to several hundred gene copies or by more subtle mechanisms, like duplication or polyploidization. In neuroblastoma, amplified MYCN is a strong prognostic indicator of poor prognosis, particularly in localized tumors where patients with normal MYCN gene dosage fare quite well. Identification of amplified MYCN in neuroblastomas has marked the clinical debut of oncogenes, and MYCN status now is being used world wide as a standard marker for neuroblastoma stratification.