The TH-MYCN neuroblastoma model overexpressing MYCN in neuroectodermal cells through the use of a tyrosine hydroxylase promoter; however, the incidence of spontaneous neuroblastoma varies between 5 and 20% in C57Bl6/N background to 40% in the 129X1/SvJ background, suggesting other genetic factors may contribute to the development of neuroblastoma (205, 207). The gene discussed is MYCN; the disease is neuroblastoma.