Clinical Application of ctDNA Dynamic Monitoring in Neoadjuvant Therapy for HER2-positive Breast Cancer Patients

This study plans to enroll 50 HER2 positive breast cancer patients in early stage (T2-3, N0-1, M0)/local late stage (T2-3, N2-3, M0 or T4a-c, Nany, M0), collect baseline tumor tissue samples of patients, as well as peripheral blood samples of multiple nodes at baseline, during new adjuvant therapy, after new adjuvant therapy (before surgery), and after surgery, detect the mutation of tumor tissue through 1021 panel, and conduct ctDNA detection of peripheral blood samples based on personalized panel design based on tumor tissue specific mutations, to explore the efficacy prediction and prognostic predictive value of ctDNA in HER2 positive new adjuvant therapy population.