The investigators want to develop a gene expression profile the for prediction the chemotherapeutic response of patients with metastatic breast cancer.

1. Metastatic breast cancer tissue is obtained from core needle biopsies pretreatment and is flash frozen and stored at -70℃ until processing.
2. After patients received docetaxel combination thiotepa for two cycles, response is assessed using Response Evaluation Criteria in Solid Tumor Group (RECIST) guidelines. Degree of response is used to divide the cancers into two groups-sensitive and resistant tumours.
3. The gene expression in metastatic breast cancer tissue sample is detected by microarray to screen gene markers that are differently expressed between groups
4. Statistical analysis is performed using unsupervised hierarchical cluster.

Inclusion Criteria:

• Patients should be histologically confirmed with metastatic breast cancer;
• Patients who had completed the planned chemotherapy regimen with no major protocol violation;
• an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2;
• At least one measurable lesion;
• Normal cardiac, hepatic, renal and bone marrow functions;
• Life expectancy ≥3 months;
• Discontinuity of previous chemotherapy for a minimum of 4 weeks.

Exclusion Criteria:

• previous history of other malignancies;
• previous surgery history on the needle biopsy organ;
• Central nervous system metastases;
• Serious or uncontrolled concurrent medical illness.

female patients with metastatic breast cancer treated by Docetaxel-based chemotherapy