Anatomic pathology selected abstracts
September 2025—The efficacy of human epidermal growth factor receptor 2 antibody-drug conjugate therapy for treating HER2-low breast cancers necessitates more accurate and reproducible HER2 IHC scoring. The authors conducted a study to validate the performance and utility of a fully automated artificial intelligence (AI) solution for interpreting HER2 IHC in breast carcinoma. In the two-arm multireader study of 120 HER2 IHC whole slide images from four sites, four surgical pathologists assessed HER2 scoring with and without the aid of an AI solution. Both arms of the study were compared with high-confidence ground truth established by agreement of at least four of five breast pathology subspecialists according to the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2018 and 2023 guidelines. The mean interobserver agreement among the ground truth pathologists across all HER2 scores was 72.4 percent (n =120).