IDH1 and astrocytoma (excluding glioblastoma): However, recent work on human samples demonstrates histologically low-grade appearing, IDH1-wildtype astrocytomas with EGFR amplification likely represent early GBMs with corresponding molecular features and poor prognosis [15, 99]; also, extrachromosomal EGFR driver mutations and amplifications are frequently detected in both human LGGs and GBMs [16].