TP53 and glioblastoma: Although little is known about the etiology of GBM or other gliomas, increased risk has been observed following exposure to ionizing radiation (8) or chemical agents or through genetic predisposition (e.g., germline TP53, NF1, and NF2 mutations) in a small proportion of the patients with GBM (e.g., Li–Fraumeni syndrome, neurofibromatosis type 1 and type 2) (8).