Through this prospective clinical trial,the investigators will focus on the relationship between circulating tumor biomarkers (i.e. circulating tumor cells, circulating tumor DNA and other biomarkers) and the status of primary tumor to discuss its application for assessing prognosis and individualized therapeutic direction. Moreover, the relationship between the circulating tumor cell subpopulations based on epithelial-mesenchymal transition and molecular pathological classification of breast cancer will be determined, which may enable the determination of the value of its application in therapeutic decision making.

Inclusion Criteria:

• Female patients aged ≥18 years with histologically confirmed breast cancer.
• The patients diagnosed with breast cancer for the first time, including postoperative patients within one month and the patients diagnosed with Stage IV breast cancer for the first time.

Exclusion Criteria:

• The patients who has begun medication for breast cancer.

The patients diagnosed with breast cancer for the first time, including postoperative patients within one month and the patients diagnosed with Stage IV breast cancer for the first time.