The fact that high polysomy of EGFR and CEP7 was also seen in IDH-mutant astrocytomas, which rarely have an EGFR amplification, and a glioblastoma appearing to evolve from a low-grade glioneuronal tumor would seem to further indicate that high polysomy is not synonymous with EGFR amplification and that an EGFR/CEP7 ratio is more useful for establishing the presence of EGFR amplification by FISH testing than solely relying on the EGFR copy number. This evidence concerns the gene IDH1 and glioblastoma.