Treatment decisions for breast cancer are usually based on traditional histopathologic findings (2), and clinically breast cancer is divided into four main subtypes with different prognoses: Luminal A, Luminal B, human epidermal growth factor receptor 2 (HER2,also known as ERBB2)-positive, and triple-negative breast cancer (TNBC) (3). Here, ERBB2 is linked to breast cancer.