Clinicopathologic factors affecting discrepancies in HER2 overexpression between core needle biopsy and surgical biopsy in breast cancer patients according to neoadjuvant treatment or not

Background: Accurate determination of human epidermal growth factor receptor 2 (HER2) status on breast core needle biopsy (CNB) tissue is important for determining neoadjuvant chemotherapies (NACs) for primary breast cancer. However, HER2 discrepancies occur before and after surgery, creating difficulties in the administration of appropriate NAC. This study aimed to identify the clinical factors affecting these discrepancies. Methods: This study...