Breast cancer is a heterogenous disease with systemic treatment options primarily based on hormone receptor and human epidermal growth factor receptor 2 (HER2) status, but also emerging therapies that target other molecular pathways involved in development, progression, resistance, and metastasis, such as antiangiogenics and poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors [5]. This evidence concerns the gene ERBB2 and breast cancer.