ERBB2 and breast cancer: Here, we design a target trial [2,4,8,9] with a protocol as similar as possible to the B-31 and N9831 trials [10–12], which estimated the effect of adjuvant trastuzumab plus chemotherapy compared with chemotherapy alone on disease-free and overall survival in individuals with early human epidermal growth factor receptor 2 (HER2)-positive breast cancer.