CDKN2A and central nervous system cancer: Over the past few decades, several biomarkers of glioma have been identified, including IDH1/IDH2 mutations, 1p19q co-deletion, CDKN2A/B homozygous deletion, chromosome 7 gains/chromosome 10 losses, PTEN deletion, monosomy 6, and genetic alterations in ATRX, BRAF, and EGFR, as well as promoter methylation of MGMT [8,15,16,17].