ERBB2 and breast cancer: Since its launch in 1998, trastuzumab became a therapeutic for breast cancer patients with HER2 overexpression and is widely administrated as approved indications in both the adjuvant and metastatic situations with the same recommended dosage.81 Trastuzumab is typically given by intravenous perfusion weekly or every 3-week cycles, at a dose based on body weight.75