A few genetic changes have been reported in MCGs, including TP53 mutation, BRCA-1 mutation, and deletion of chromosome 1p36, whereas TP53 mutation and PDGFR (platelet-derived growth factor receptor) overexpression represent early changes during low-grade glioma development, anaplastic progression is associated with pRB alteration and loss of heterozygosity (LOH) of 19q, further malignant progression to glioblastoma multiform including LOH 10q and mutations of PTEN gene. The gene discussed is PTEN; the disease is glioblastoma.