failure to anthracycline and/or taxol chemotherapy;

metastatic tumor is histologically confirmed by immunohistochemical staining to be er-negative and pr-negative. fish testing for her-2-negative;

metastatic tumor can not be removed through surgery procedure;

an eastern cooperative oncology group (ecog) performance status of 0-2;

normal cardiac, hepatic, renal and bone marrow functions;

life expectancy ≥3 months.

central nervous system metastases;

serious or uncontrolled concurrent medical illness;

history of other malignancies;

having been enrolled in some other clinal trials within a month;