EGFR and glioblastoma: In GBM, FAK, encoded by the protein tyrosine kinase 2 (PTK2) gene, and its paralog PYK2, encoded by the PTK2B gene, are frequently activated downstream of integrin and receptor tyrosine kinase (RTK) signaling, particularly involving the epidermal growth factor receptor (EGFR) and its mutant form EGFRvIII (22).