Based on the TCGA data, the most frequently mutated genes in lower-grade glioma (WHO grade II- grade III) were IDH1 (77.25%), TP53 (48.04%), ATRX (39.22%), CIC (22.75%), TTN (17.06%), PIK3CA (8.43%) and EGFR (6.86%), and the most prevalent mutations in glioblastoma (GBM) were PTEN (34.86%), TTN (32.57%), TP53 (31.55%), EGFR (26.97%), MUC16 (18.07%) and NF1 (12.98%). The gene discussed is PTEN; the disease is glioblastoma.