Concordance Between Core Needle Biopsy and Surgical Specimens in Determining Molecular Biological Subtypes of Breast Cancer by Immunohistochemistry

Abstract

Background: Breast carcinoma is the most common malignancy among women around the world. Core needle biopsy provides samples that are adequate in size thus allowing a histological diagnosis of breast carcinomas. CNB specimens can also be used for the immunohistochemical (IHC) assays of hormone receptors. Aims: To evaluate the concordance of ER, PR, HER2 Neu and Ki-67 in core needle biopsy and surgical specimens obtained by Modified radical mastectomy (MRM). Methods: A cross-sectional observational study was conducted in the Department of Pathology in association with the Department of Surgery at Murshidabad Medical College and Hospital for a duration of one and a half years. Patients undergoing Core needle biopsy of the breast who have been diagnosed with breast carcinoma on the basis of histopathology report and subsequently planned for MRM who have given consent for the study were included in this study. The samples were classified according to the immunohistochemical staining into four molecular subtypes: Luminal A, Luminal B, HER 2 Neu enriched, and triple-negative subtype depending on the expression of ER, PR, HER 2 Neu, and Ki-67. Result: The most common molecular subtype of breast carcinoma in both CNB and MRM specimens was the Triple-negative subtype. Conclusion: CNB has been found to be a reliable diagnostic tool that can help in determining Histopathological biomarkers for ER, PR positive, and HER2 Neu positive or negative tumors and it has also been found that retesting these markers again on the surgical specimens may not be necessary. Keywords: Core needle biopsy, Breast carcinoma, Molecular subtyping, Immunohistochemistry