Dexmedetomidine is widely used as an anaesthetic for general anesthesia during surgery. Previous studies in cells and animals show that dexmedetomidine may promote cancer growth. Using serum from breast cancer surgery patients randomized to receive dexmedetomidine or saline during surgery, we investigated the effects of dexmedetomidine on proliferation, migration and metastasis in MCF-7 breast cancer cells in vitro.

Women diagnosed with breast cancer undergoing elective surgery under general anesthesia will be randomly allocated to dexmedetomidine group or control group. Patients from both groups will receive midazolam, propofol, fentanyl, remifentanil and CIS atracurium for total intravenous anesthesia. BIS value will be controlled between 40-60 during surgery. Patients of dexmedetomidine group will receive a loading does of 1ug/kg dexmedetomidine since 15 mins before induction, and receive another 1ug/kg of dexmedetomidine at a rate of 0.5ug/kg/h for 2 continuous hours during surgery. Patients of control group will receive same amount of normal saline. Serum will be collected from patients of both groups at before induction and 1h post-surgery. The MCF-7 breast cancer cell line will be treated with patient serum from both groups. The effects of dexmedetomidine on cellular proliferation, migration and metastasis will be measured.

Inclusion Criteria:

• ASA grade I-III Age range of 18 to75 Patients diagnosed primary breast cancer(T2-3, N0-2, M0) Patients will have elective adenomammectomy

Exclusion Criteria:

• with history of breast operation Patients diagnosed carcinoma erysipelatodes Severe liver, renal, brain or lung disease with history of opioid addiction Patients diagnosed metastatic breast cancer