ERBB2 and breast cancer: When the HER2 status of breast cancer tissues obtained from biopsy before chemotherapy and surgery is categorized as score 3 in HER2 testing by IHC-DAB or over score 2.0 in HER2 testing by FISH, anthracycline, a topoisomerase inhibitor, is administered for three months and is followed by trastuzumab and taxanes, paclitaxel, or docetaxel, which are microtubule inhibitors, for three months24.