EGFR and central nervous system cancer: For example, EGFR family receptors are amplified and/or mutated in various human tumors, including gliomas, non‐small‐cell lung carcinoma, breast, gastric, and ovarian cancers.205, 206 Amplification or mutation of EGFR‐family receptors can cause overexpression and/or constitutive activation of EGFR signaling in these tumor tissues.205, 206, 207 Activation of EGFR results in the recruitment of Grb2, a SH2 domain protein complexed with the guanine exchange factor son‐of‐sevenless (Sos), to the tyrosine‐phosphorylated EGFR.