Standardimmunohistochemistry (IHC) labeling of tumor tissue biopsies, obtained byimaging molecular targets such as the estrogen receptor (ER), progesteronereceptor (PR), and human epidermal growth factor receptor 2 (HER2)facilitates oncologists in determining both prognosis and treatmentstrategies for individual patients with breast cancer. The gene discussed is ERBB2; the disease is breast cancer.