Evaluation of Ki-67 Index in Core Needle Biopsies and Matched Breast Cancer Surgical Specimens

Context.— The Ki-67 index is strongly prognostic and is used as a surrogate marker to distinguish luminal A from luminal B breast cancer types. Objective.— To investigate differences in Ki-67 index between core needle biopsy samples and matched surgical samples in breast cancer. Design.— We included patients with invasive breast cancer who did not receive neoadjuvant therapy. A total of 89 pairs of core needle biopsies and surgical specimens...