In contrast, hGFAP-cre::CrebbpFl/Fl::lsl-MYCNFl/Wtmice with one additional copy of exogeneous MYCN, also developed brain tumor although the penetrance for brain tumors was slightly lower (approx. 25% in 6 months) (SFig. 1A). This evidence concerns the gene HGFAC and brain neoplasm.