For example, a panel of PD GBM lines originally developed by a group at the Mayo Clinic varied greatly across each sample in terms of well-established GBM mutations, including epidermal growth factor receptor (EGFR), phosphatase and tensin homologue (PTEN), p53, and platelet derived growth factor receptors A (PDGFRA) [25]. This evidence concerns the gene PTEN and glioblastoma.