EGFR and breast cancer: EGFR participates in the ERBB signaling pathway, whereas MET is expressed in its alternative pathway, and GSK3B is situated in its downstream pathway known as the PI3K–Akt signaling pathway (Figure 2) (44), which plays critical roles in NSCLC, breast cancer, glioma, etc. According to previous reports, EGFR on the plasma membrane is the receptor for epithelial growth factor (EGF), and mutation or overexpression of EGFR is associated with tumor cell proliferation, angiogenesis, invasion, metastasis, and apoptosis (45).