ERBB2 and breast carcinoma: Given the strong immunostaining for HER2/neu and the known benefit of combining HER2-directed therapy with chemotherapy in HER2-overexpressing breast carcinoma, therapy was initiated with trastuzumab 6 mg/kg every 21 days and capecitabine 2000 mg/m2 days 1-14 of a 21 day cycle [5].