In the case of GBM, the presence of homozygous deletion of CDKN2A/B, mutation of the TERT promoter, amplification of the EGFR gene, alterations in the number of copies of chromosomes 7 and 10 (+7/−10), microvascular proliferation and necrosis are the characteristics that result in the highest classification grade [1,69]. Here, TERT is linked to glioblastoma.