The epidermal growth factor receptor (EGFR), called Erb-B2 receptor tyrosine kinase 1 (ErbB1)/human epidermal growth factor receptor 1 (HER1), is the most well-established receptor tyrosine kinase (RTK), and overactivation of the EGFR signaling pathway is strongly linked to various types of cancer, such as non–small-cell lung cancer, breast cancer, and glioblastoma (1). The gene discussed is EGFR; the disease is breast cancer.