Breast cancer, metastatic breast cancer, hormone receptor positive malignant neoplasm of breast, stage 0 breast carcinoma, breast neoplasms, stage I breast carcinoma, stage II breast carcinoma, stage III breast carcinoma,HER-2 positive breast cancer, locally advanced malignant neoplasm, human epidermal growth factor 2 negative carcinoma of breast, atypical ductal breast hyperplasia, BRCA1 & BRCA2 mutation carrier, ductal breast carcinoma in situ, lobular breast carcinoma in situ. The gene discussed is ERBB2; the disease is breast cancer.