CK19 Combined With Contrast-enhanced Ultrasound: a Prediction System on Axillary Lymph Node Metastasis in Breast Cancer

Inclusion Criteria: 1. female, age 18\~70 years old 2. the test group should be in accordance with the pathological diagnosis of breast cancer, the clinical stage of breast cancer (stage cTis, cI, cII and cT3N1M0), the initial treatment to receive surgical treatment. Complete preoperative clinical diagnosis data, including the ipsilateral axillary lymph node CEUS data and peripheral blood sample; The negative-control group should comply with the pathological diagnosis, breast adenosis, fibrocystic lesions, breast cysts and other benign lesions, with complete preoperative clinical data, also including ipsilateral axillary lymph node CEUS data and peripheral blood sample Exclusion criteria: 1. metastatic breast cancer, inflammatory breast disease, surgery without lymph node staging 2. pregnancy or lactation 3. patients with hematopoietic system disease or cancer, autoimmune diseases 4. preservation of substandard peripheral blood samples.