The proto-oncogene N-MYC; a transcription factor which plays a role in regulation of cell growth and proliferation, is mainly expressed in the developing nervous system and is critical during neural crest embryogenesis. Overexpression of N-MYC seems to block differentiation and increase cell proliferation, this is the most important unfavourable prognostic factor for neuroblastoma and it is amplified in 25% of cases. Neuroblastoma is a dominating group of neuron tumours and is one of the most common solid tumours in children.
