ERBB2 and metastatic neoplasm: Patients with HER2-positive core needle biopsy samples, with metastatic disease, with missing data or with previous endocrine therapy were not eligible for this study.Patients missing relevant information, who were HER2-positive or who had received neoadjuvant chemotherapy regimens other than cyclophosphamide, epirubicin and 5-fluorouracil, cyclophosphamide, epirubicin and 5-fluorouracil followed by paclitaxel or docetaxel and epirubicin, navelbine and epirubicin or paclitaxel and carboplatin or paclitaxel and cisplatin were excluded from our study.