The classifications of primary glioblastomas are based on classic mutations, including IDH mutations, 1p/19q codeletion, MGMT promoter methylation, G-CIMP (glioma-CpG island methylator phenotype) methylation, TERT (telomerase reverse transcriptase) promoter mutations, EGFR genomic alterations/mutations, LOH (loss of heterozygosity) at 10q, p16/INK4A deletion, and PTEN (phosphatase and tensin homolog) mutations [4–8]. The gene discussed is CDKN2A; the disease is glioma.