Clinical Application of ctDNA in Early Screening of Breast Cancer

Inclusion Criteria: * Written informed consent must be obtained and documented according to the local regulatory requirements prior to beginning specific protocol procedures. * Age of at least 18 and at most 70 years. * Normal people who works as the volunteers. * Benign breast disease patients should be diagnosed with confirmed pathology after surgery. * Breast cancer patients should be diagnosed with confirmed pathology after surgery, and with no clinical evidence of local recurrence or distant metastases. Complete staging work-up within 3 months prior to registration, which should be earlier than TNM IIA stage. * Adequate organ function including normal red and white blood count, platelets, serum creatinine, bilirubin, and transaminases within normal range of the institution. Exclusion Criteria: * Known hypersensitivity reaction to the investigational compounds or incorporated substances. * Local recurrence and/or metastasis of breast cancer. * Pregnant or lactating patients. Patients of childbearing potential must have a negative pregnancy test (urine or serum) within 14 days prior to registration. * Prior or concomitant secondary malignancy (except non-melanomatous skin cancer or carcinoma in situ of the uterine cervix). * Other serious illness or medical condition that may interfere with the understanding and giving of informed consent and the conduct of the study. * Concurrent treatment with other experimental drugs or any other anti-cancer therapy. * Males.