is a member of the family of proto-oncogenes. It encodes a transcription factor, MYCN, involved in the control of fundamental processes during embryonal development. The MYCN protein is situated downstream of several signaling pathways promoting cell growth, proliferation and metabolism of progenitor cells in different developing organs and tissues. Conversely, deregulated MYCN signaling supports the development of several different tumors, mainly with a childhood onset, including neuroblastoma, medulloblastoma, rhabdomyosarcoma and Wilms' tumor, but it is also associated with some cancers occurring during adulthood such as prostate and lung cancer. In neuroblastoma, -amplification is the most consistent genetic aberration associated with poor prognosis and treatment failure. Targeting MYCN has been proposed as a therapeutic strategy for the treatment of these tumors and great efforts have allowed the development of direct and indirect MYCN inhibitors with potential clinical use.