EGFR (HER1) and ERBB2 (HER2) are frequently implicated in breast, lung, ovarian, and other malignancies, whereas ERBB3 (HER3) is commonly associated with breast cancer, and ERBB4 (HER4) has been detected in both breast cancer and granulosa cell tumors [4]. The gene discussed is ERBB2; the disease is breast cancer.