In general, the development of brain metastases from breast cancer depends on several prognostic factors, including younger age, ethnicity, hormone receptor negative status, presence of BRCA1 germ-line mutations, and the expression of the epidermal growth factor receptor 2 (Her2/neu) proto-oncogene, all of which contribute to an increased rate of brain metastasis [2]. The gene discussed is ERBB2; the disease is breast cancer.