Other variants

Pediatric patients with glioblastoma multiforme high-grade glioma whose tumors lack both histone variants and IDH1 variants represent approximately 40% of pediatric glioblastoma multiforme cases.[10,52] This is a heterogeneous group, with higher rates of gene amplifications than other pediatric high-grade glioma subtypes. The most commonly amplified genes are PDGFRA, EGFR, CCND/CDK, and MYC/MYCN.[36,37] MGMT promoter methylation rates are low in this group.[52] One report divided this group into three subtypes. The subtype characterized by high rates of MYCN amplification showed the poorest prognosis, while the subtype characterized by TERT promoter variants and EGFR amplification showed the most favorable prognosis. The third group was characterized by PDGFRA amplification.[52]