IDH1 and astrocytoma (excluding glioblastoma): We demonstrate the propensity for at least low-level EGFR amplification in these IDH wildtype lesions.87,88 We replicate the association of IDH mutants with ATRX loss in astrocytoma, and of TERT mutations, ATRX retention, and 1p/19q codeletions with oligodendrogliomas.83-86,88-90 Within the finer IDH-mutant landscape, we demonstrate a strong association between IDH1 C394A mutants, TERT wildtype, no EGFR amplification, and ATRX loss in astrocytoma.