Neuroendocrine tumors arose in around 60% of hGFAP-cre::lsl-MYCN mice with two extra copies of MYCN, mostly between 6 and 11 months of age, while mice with only one additional copy of exogenous MYCN stayed tumor-free (SFig. 1A, ref. [28]). This evidence concerns the gene MYCN and neuroendocrine neoplasm.