Characterization of 47 tumors from 45 patients reveals that these gliomas are predominantly supratentorial in young adults, are highly infiltrative, and harbor mitogen-activated protein kinase (MAPK) pathway alterations with high rates of CDKN2A/2B deletion, PDGFRA amplification, MYCN amplification, NF1 variants, and BRAF alterations. The gene discussed is MYCN; the disease is central nervous system cancer.