These observations prompted us to investigate whether multipotent NCSCs can also serve as NB cell of origin in vivo. Since MYCN amplification is the most common genetic aberration in sporadic NB and occurs in approximately 25 percent of tumors [2], we used LSL-MYCN mice, a genetically engineered mouse model in which MYCN oncogene is activated upon Cre-mediated recombination [14]. This evidence concerns the gene MYCN and neuroblastoma.