ERBB2 and neoplasm: Among prognostic factors used in clinical practice to determine the type of treatment indicated for each patient, the presence of metastatic axillary lymph nodes has been shown to be the most valuable, followed by expression of hormonal receptors, human epidermal growth factor receptor 2 (HER2/neu) status, tumor size, histological subtype, tumor grade, lymphovascular invasion and proliferative rate [18].