PTEN and glioblastoma: Several characteristic molecular aberrations have been described in GBM, including chromosome 7 amplification and 10 deletions, mutations of IDH1&2, tumor protein p53 (TP53), platelet‐derived growth factor receptor alpha (PDGFRA), epidermal growth factor receptor (EGFR), neurofibromatosis type 1 gene (NF1), telomerase reverse transcriptase gene promotor (TERTp) and PTEN.97