China CellSearch Study

Inclusion Criteria * Female * over 18 and less than 70 years of age * Subject having agreed to participate in the study and follow the study procedures by providing written informed consent prior entering the study. * For MBC Subject Set only Confirmed metastatic breast cancer patient with at least one measurable solid tumor according to the RECIST guideline Starting a new line of systemic therapy which is recommended in the Chinese edition of NCCN Clinical Practice Guidelines in Oncology Breast Cancer Guideline 2009 line of chemotherapy should be over 3 ECOG performance grade of 0 to 2 Life expectancy over 3 months * For Healthy Subject Set only Medical examinations detect no breast benign and malignant tumors * For Benign Breast Disease Subject Set only Pathology diagnosed breast benign tumor disease Exclusion Criteria * Self reported pregnancy * For MBC Subject Set only Prior history of other malignancy Patients who have surgery to remove any metastatic lesions or receive radiation therapy during her participation in the study * For Healthy Subject Set only Prior history of breast benign tumor disease or any malignancy Any conditions inappropriate for blood drawing * For Benign Breast Disease Subject Set only Prior history of any malignancy Any conditions inappropriate for blood drawing