Approximately one-third to half of the patients with human epidermal growth factor receptor 2 positive (HER2+), one-third of those with triple-negative breast cancer (TNBC), and 15% with hormone receptor-positive, HER2-negative (HR + HER2-) metastatic BC subtypes will develop brain metastases during their respective course of illness [1]. Here, ERBB2 is linked to breast cancer.