{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T13:14:48Z","timestamp":1792242888273,"version":"4.4.0"},"reference-count":31,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,1,3]],"date-time":"2023-01-03T00:00:00Z","timestamp":1672704000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>The expression of human epidermal growth factor receptor 2 (HER2) protein or gene transcripts is critical for therapeutic decision making in breast cancer. We examined the performance of a digitalized and artificial intelligence (AI)-assisted workflow for HER2 status determination in accordance with the American Society of Clinical Oncology (ASCO)\/College of Pathologists (CAP) guidelines. Our preliminary cohort consisted of 495 primary breast carcinomas, and our study cohort included 67 primary breast carcinomas and 30 metastatic deposits, which were evaluated for HER2 status by immunohistochemistry (IHC) and in situ hybridization (ISH). Three practicing breast pathologists independently assessed and scored slides, building the ground truth. Following a washout period, pathologists were provided with the results of the AI digital image analysis (DIA) and asked to reassess the slides. Both rounds of assessment from the pathologists were compared to the AI results and ground truth for each slide. We observed an overall HER2 positivity rate of 15% in our study cohort. Moderate agreement (Cohen\u2019s \u03ba 0.59) was observed between the ground truth and AI on IHC, with most discrepancies occurring between 0 and 1+ scores. Inter-observer agreement amongst pathologists was substantial (Fleiss\u00b4 \u03ba 0.77) and pathologists\u2019 agreement with AI scores was 80.6%. Substantial agreement of the AI with the ground truth (Cohen\u00b4s \u03ba 0.80) was detected on ISH-stained slides, and the accuracy of AI was similar for the primary and metastatic tumors. We demonstrated the feasibility of a combined HER2 IHC and ISH AI workflow, with a Cohen\u2019s \u03ba of 0.94 when assessed in accordance with the ASCO\/CAP recommendations.<\/jats:p>","DOI":"10.3390\/diagnostics13010168","type":"journal-article","created":{"date-parts":[[2023,1,4]],"date-time":"2023-01-04T01:42:44Z","timestamp":1672796564000},"page":"168","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":48,"title":["Determining HER2 Status by Artificial Intelligence: An Investigation of Primary, Metastatic, and HER2 Low Breast Tumors"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7059-8210","authenticated-orcid":false,"given":"Christiane","family":"Palm","sequence":"first","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"},{"name":"Faculty of Medicine, University of Zurich, 8006 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catherine E.","family":"Connolly","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Regina","family":"Masser","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara","family":"Padberg Sgier","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eva","family":"Karamitopoulou","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Quentin","family":"Simon","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Beata","family":"Bode","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"},{"name":"Faculty of Medicine, University of Zurich, 8006 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8571-7446","authenticated-orcid":false,"given":"Marianne","family":"Tinguely","sequence":"additional","affiliation":[{"name":"Pathologie Institute Enge, 8005 Zurich, Switzerland"},{"name":"Faculty of Medicine, University of Zurich, 8006 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1706","DOI":"10.1158\/1078-0432.CCR-0951-3","article-title":"Association between HER-2\/neu and Vascular Endothelial Growth Factor Expression Predicts Clinical Outcome in Primary Breast Cancer Patients","volume":"10","author":"Konecny","year":"2004","journal-title":"Clin. Cancer Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"34","DOI":"10.4132\/jptm.2019.11.03","article-title":"HER2 status in breast cancer: Changes in guidelines and complicating factors for interpretation","volume":"54","author":"Ahn","year":"2020","journal-title":"J. Pathol. Transl. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1126\/science.3798106","article-title":"Human breast cancer: Correlation of relapse and survival with amplification of the HER-2\/neu oncogene","volume":"235","author":"Slamon","year":"1987","journal-title":"Science"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Patel, A., Unni, N., and Peng, Y. (2020). The Changing Paradigm for the Treatment of HER2-Positive Breast Cancer. Cancers, 12.","DOI":"10.3390\/cancers12082081"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.1016\/S0140-6736(16)32616-2","article-title":"11 years\u2019 follow-up of trastuzumab after adjuvant chemotherapy in HER2-positive early breast cancer: Final analysis of the HERceptin Adjuvant (HERA) trial","volume":"389","author":"Cameron","year":"2017","journal-title":"Lancet"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2105","DOI":"10.1200\/JCO.2018.77.8738","article-title":"Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology\/College of American Pathologists Clinical Practice Guideline Focused Update","volume":"36","author":"Wolff","year":"2018","journal-title":"J. Clin. Oncol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/j.prp.2015.11.016","article-title":"Interobserver reproducibility for HER2\/neu immunohistochemistry: A comparison of reproducibility for the HercepTest\u2122 and the 4B5 antibody clone","volume":"212","author":"Layfield","year":"2016","journal-title":"Pathol. Res. Pract."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1038\/modpathol.3880440","article-title":"HER-2\/neu in Breast Cancer: Interobserver Variability and Performance of Immunohistochemistry with 4 Antibodies Compared with Fluorescent In Situ Hybridization","volume":"14","author":"Thomson","year":"2001","journal-title":"Mod. Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1016\/j.critrevonc.2010.12.005","article-title":"Current technologies for HER2 testing in breast cancer","volume":"80","author":"Moelans","year":"2011","journal-title":"Crit. Rev. Oncol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1056\/NEJMoa2203690","article-title":"Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer","volume":"387","author":"Modi","year":"2022","journal-title":"N. Engl. J. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1056\/NEJMe2206661","article-title":"DESTINY-Changing Results for Advanced Breast Cancer","volume":"387","author":"Hurvitz","year":"2022","journal-title":"N. Engl. J. Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1186\/1471-2407-9-165","article-title":"Inter-observer reproducibility of HER2 immunohistochemical assessment and concordance with fluorescent in situhybridization (FISH): Pathologist assessment compared to quantitative image analysis","volume":"9","author":"Turashvili","year":"2009","journal-title":"BMC Cancer"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"710","DOI":"10.1136\/jcp.2004.023424","article-title":"HER2 amplification status in breast cancer: A comparison between immunohistochemical staining and fluorescence in situ hybridisation using manual and automated quantitative image analysis scoring techniques","volume":"58","author":"Ellis","year":"2005","journal-title":"J. Clin. Pathol."},{"key":"ref_14","first-page":"41","article-title":"Digital image analysis of membrane connectivity is a robust measure of HER2 immunostains","volume":"132","author":"Eld","year":"2011","journal-title":"Breast Cancer Res. Treat."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1109\/TMI.2009.2012901","article-title":"Automated Quantitative Assessment of HER-2\/neu Immunohistochemical Expression in Breast Cancer","volume":"28","author":"Masmoudi","year":"2009","journal-title":"IEEE Trans. Med. Imaging"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"899","DOI":"10.1093\/ajcp\/aqab206","article-title":"Quantitative Image Analysis as an Adjunct to Manual Scoring of ER, PgR, and HER2 in Invasive Breast Carcinoma","volume":"157","author":"Yousif","year":"2021","journal-title":"Am. J. Clin. Pathol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1007\/s00428-021-03154-x","article-title":"Can AI-assisted microscope facilitate breast HER2 interpretation? A multi-institutional ring study","volume":"479","author":"Yue","year":"2021","journal-title":"Virchows Arch."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e197700","DOI":"10.1001\/jamanetworkopen.2019.7700","article-title":"Artificial Intelligence Algorithms to Assess Hormonal Status From Tissue Microarrays in Patients With Breast Cancer","volume":"2","author":"Shamai","year":"2019","journal-title":"JAMA Netw. Open"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1111\/his.13333","article-title":"HER2 challenge contest: A detailed assessment of automated HER2 scoring algorithms in whole slide images of breast cancer tissues","volume":"72","author":"Qaiser","year":"2017","journal-title":"Histopathology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"159","DOI":"10.2307\/2529310","article-title":"The Measurement of Observer Agreement for Categorical Data","volume":"33","author":"Landis","year":"1977","journal-title":"Biometrics"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"917","DOI":"10.1111\/his.13812","article-title":"What is the added value of digital image analysis of HER 2 immunohistochemistry in breast cancer in clinical practice? A study with multiple platforms","volume":"74","author":"Koopman","year":"2018","journal-title":"Histopathology"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1007\/s00428-015-1868-7","article-title":"Free digital image analysis software helps to resolve equivocal scores in HER2 immunohistochemistry","volume":"468","author":"Helin","year":"2015","journal-title":"Virchows Arch."},{"key":"ref_23","first-page":"217","article-title":"Assessing HER2 testing quality in breast cancer: Variables that influence HER2 positivity rate from a large, multicenter, observational study in Germany","volume":"30","author":"Lebeau","year":"2016","journal-title":"Mod. Pathol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1124","DOI":"10.3389\/fonc.2019.01124","article-title":"Deciphering HER2 Breast Cancer Disease: Biological and Clinical Implications","volume":"9","author":"Parrado","year":"2019","journal-title":"Front. Oncol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1180","DOI":"10.5858\/arpa.2018-0378-CP","article-title":"Quantitative Image Analysis of Human Epidermal Growth Factor Receptor 2 Immunohistochemistry for Breast Cancer: Guideline From the College of American Pathologists","volume":"143","author":"Bui","year":"2018","journal-title":"Arch. Pathol. Lab. Med."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1101","DOI":"10.1038\/s41374-022-00804-9","article-title":"Quantitative measurement of HER2 expression to subclassify ERBB2 unamplified breast cancer","volume":"102","author":"Moutafi","year":"2022","journal-title":"Lab. Investig."},{"key":"ref_27","first-page":"123","article-title":"Evolving concepts in HER2 evaluation in breast cancer: Heterogeneity, HER2-low carcinomas and beyond","volume":"72","author":"Annaratone","year":"2020","journal-title":"Semin. Cancer Biol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2255","DOI":"10.21037\/tlcr-20-591","article-title":"A narrative review of digital pathology and artificial intelligence: Focusing on lung cancer","volume":"9","author":"Sakamoto","year":"2020","journal-title":"Transl. Lung Cancer Res."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Jahn, S., Plass, M., and Moinfar, F. (2020). Digital Pathology: Advantages, Limitations and Emerging Perspectives. J. Clin. Med., 9.","DOI":"10.3390\/jcm9113697"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1186\/s13000-021-01085-4","article-title":"Artificial intelligence (AI) in medicine, current applications and future role with special emphasis on its potential and promise in pathology: Present and future impact, obstacles including costs and acceptance among pathologists, practical and philosophical considerations. A comprehensive review","volume":"16","author":"Ahmad","year":"2021","journal-title":"Diagn. Pathol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1186\/1471-2407-13-615","article-title":"Assessment of HER2 status in breast cancer: Overall positivity rate and accuracy by fluorescence in situ hybridization and immunohistochemistry in a single institution over 12 years: A quality control study","volume":"13","author":"Varga","year":"2013","journal-title":"BMC Cancer"}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/13\/1\/168\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T17:58:06Z","timestamp":1760119086000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/13\/1\/168"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,3]]},"references-count":31,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["diagnostics13010168"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics13010168","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,3]]}}}