EGFR and breast cancer: Overexpression of wild-type (WT) EGFR protein with or without EGFR gene amplification or a kinase-activating mutation further enhances cell proliferation, migration, survival, and antiapoptotic responses through signaling cascades, and these processes are closely related to the occurrence and development of many types of epithelial-derived cancer, such as non-small cell lung cancer (NSCLC), breast cancer, glioma, head and neck cancer, cervical cancer, and bladder cancer.