IDH1 and glioblastoma: While this case showed additional characteristics of astrocytic lineage, including gain of chromosome 7 and heterozygous deletion of 9p, it lacked typical alterations of primary GBM such as EGFR amplification, chromosome 10 loss and homozygous deletion of CDKN2A. Taken together, these findings are most consistent with an IDH mutant GBM, often referred to clinically as “secondary” GBM.