EGFR and gliosarcoma: We first validated the model through a thorough histopathological assessment, which extended previous observations30, confirming that in mouse the Ink4a/Arf−/−; EGFR* combination recapitulates a broad range of HGG, ranging from anaplastic astrocytomas, oligodendrogliomas and oligoastrocytomas to GBM and gliosarcoma (Supplementary Fig. 1b,c).