Evaluation of the Relationship of TOP2α Expression and Effect of Non Dose-dense Chemotherapy for Breast Cancer

800 breast cancer patients who have received chemotherapy prior to this study will be enrolled in the group, including 400 patients received the anthracyclines followed taxanes chemotherapy(Epirubicin 90 mg/m2 d1, Cyclophosphamide 600mg/m2 d1，21days/cycle, 4 cycles, followed by Docetaxel 75mg/m2,d1, 21days/cycle, 4 cycles;or paclitaxel：Epirubicin 90 mg/m2 d1 cyclophosphamide 600mg/m2 d1, 21day/cycle, 4 cycles, followed by paclitaxel 80mg/m2, weekly, 12 wks), and the other 400 patients who have received regiments containing no taxanes (FEC：5-FU 600mg/m2 d1,Epirubicin 90mg/m2 d1, Cyclophosphamide 500mg/m2 d1, 21day/cycle, 6 cycles; or EC: Epirubicin 90mg/m2 d1, Cyclophosphamide 500mg/m2 d1,21 day/cycle, 6 cycles).The patients will be enrolled in the groups within one month after chemotherapy.Three tumor tissue slices of all the enrolled patients will be collected for TOP2α assay. Meanwhile, 10 years followed-up survey will be conducted. The relationship of TOP2α expression and 5-year or 10-year disease free survival(DFS) and overall survival（OS）will be identified in this study.