Zavitsanos et al. performed a matched pair analysis of breast cancer patients with and without mutations in BRCA1/2 and found that germline BRCA1 mutations in breast cancer patients associated with increased risk of brain metastasis, even when accounting for other confounding factors, such as age, stage, and expression of hormone receptors ER and human epidermal growth factor receptor 2 (HER2) [20]. Here, ERBB2 is linked to breast cancer.