One of the reasons is that BC is a complex disease, with its etiology involving both environmental and hereditary factors; it is also highly heterogeneous, as it is typically classified into six molecular subtypes: luminal A, luminal B, normal-like, basal (also known as triple-negative), HER+, and claudin-low based on their unique phenotypes and molecular characteristics, such as hormone receptors and human EGF-like receptor 2 (HER2) receptor status (Dai et al., 2017). Here, ERBB2 is linked to breast cancer.