{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T19:55:18Z","timestamp":1782849318855,"version":"3.54.5"},"reference-count":40,"publisher":"SAGE Publications","license":[{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Ther Adv Med Oncol"],"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Receptor conversion, including changes in human epidermal growth factor receptor 2 (HER2) expression, has been reported after neoadjuvant therapy (NAT), but determinants of HER2 changes between baseline biopsy and residual disease remain incompletely understood.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective:<\/jats:title>\n                    <jats:p>To evaluate the rate of HER2 status conversion after NAT and to identify factors associated with these changes in the context of contemporary treatment standards.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design:<\/jats:title>\n                    <jats:p>Retrospective analysis of patients with breast cancer (BC) treated with NAT followed by surgery between January 2019 and June 2024.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>BC was classified as HER2-0, HER2-low, or HER2-positive. HER2 expression before and after NAT was compared. Probabilities of HER2 subtype conversion were estimated, and univariable and multivariable analyses were performed to assess clinicopathological factors associated with HER2 status changes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      A total of 736 patients were included in the analysis, with HER2 status conversion observed in 34.2% (252\/736) patients. The shift in HER2 expression occurred in 38.5% (94\/244) of HER2-0, 27.9% (95\/340) of HER2-low, and 41.4% (63\/152) of HER2-positive tumors. A decrease in HER2 status was significantly more common than an increase (29.7% vs 18.2%;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001). The acquisition of HER2 positivity from initially HER2-0\/low tumors was rare, occurring in only 19\/584 (3.3%) cases. Downregulation of HER2 status from HER2-positive to HER2-0\/low was more frequently observed in tumors initially classified as HER2 2+ with a positive fluorescence in situ hybridization (FISH) result compared to HER2 3+ tumors (adjusted odds ratio (OR\n                      <jats:sub>adj<\/jats:sub>\n                      )\u2009=\u20092.43, 95% confidence interval (CI): 1.18\u20135.01;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.017). Similarly, the conversion from HER2-low to HER2-0 was observed more often in tumors initially classified as HER2 1+ compared to HER2 2+ with a negative FISH result (OR\n                      <jats:sub>adj<\/jats:sub>\n                      \u2009=\u20093.14; 95% CI: 1.20\u20138.22;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.009). Conversely, the acquisition of HER2 positivity was significantly associated with high-grade (G3) tumors (OR\n                      <jats:sub>adj<\/jats:sub>\n                      \u2009=\u20095.50; 95% CI: 2.12\u201314.3;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001) and estrogen receptor expression &gt;10% (OR\n                      <jats:sub>adj<\/jats:sub>\n                      \u2009=\u20098.61; 95% CI: 1.09\u201368.1;\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.041).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>HER2 status conversion affects about one-third of BCs after NAT, most commonly as downregulation, supporting HER2 reassessment in residual disease to guide post-NAT treatment decisions.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/17588359261451850","type":"journal-article","created":{"date-parts":[[2026,6,28]],"date-time":"2026-06-28T12:33:51Z","timestamp":1782650031000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Dynamics of HER2 status following neoadjuvant systemic therapy in breast cancer: a large single-center cohort analysis"],"prefix":"10.1177","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9902-711X","authenticated-orcid":false,"given":"Katarzyna","family":"Pogoda","sequence":"first","affiliation":[{"name":"Department of Breast Cancer and Reconstructive Surgery, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw 02781, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Magdalena","family":"Czopowicz","sequence":"additional","affiliation":[{"name":"National Cancer Strategy Department, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Agata","family":"Bak","sequence":"additional","affiliation":[{"name":"National Cancer Strategy Department, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wojciech","family":"Olszewski","sequence":"additional","affiliation":[{"name":"Department of Pathology, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michal","family":"Czopowicz","sequence":"additional","affiliation":[{"name":"Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Durzynska","sequence":"additional","affiliation":[{"name":"Department of Pathology, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dorota","family":"Najmrocka","sequence":"additional","affiliation":[{"name":"National Cancer Strategy Department, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paulina","family":"Halasa","sequence":"additional","affiliation":[{"name":"National Cancer Strategy Department, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Borowiec","sequence":"additional","affiliation":[{"name":"Non-Commercial Clinical Research Outpatient Clinic, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zbigniew","family":"Nowecki","sequence":"additional","affiliation":[{"name":"Department of Breast Cancer and Reconstructive Surgery, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Niwinska","sequence":"additional","affiliation":[{"name":"Department of Radiation Therapy, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,6,28]]},"reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.annonc.2023.11.016"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(13)62422-8"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1158\/1078-0432.CCR-19-3492"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.breast.2025.104516"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.humpath.2016.12.019"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1245\/s10434-018-6608-1"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.annonc.2021.09.019"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejca.2024.113920"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1111\/his.15426"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41379-019-0326-5"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1470-2045(21)00301-6"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.19.02488"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2203690"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2407086"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1177\/17588359241297079"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(07)61602-X"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.22.02864"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.19.02309"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1093\/annonc\/mdt303"},{"key":"e_1_3_4_21_2","first-page":"46","volume-title":"Statistics with confidence","author":"Altman DG","year":"2000","unstructured":"Altman DG, Machin D, Bryant TN, et al. Statistics with confidence. 2nd ed. Bristol: BMJ Books, 2000, pp. 46\u201355.","edition":"2"},{"key":"e_1_3_4_22_2","volume-title":"Handbook of inter-rater reliability: the definitive guide to measuring the extent of agreement among raters","author":"Gwet K.","year":"2014","unstructured":"Gwet K. Handbook of inter-rater reliability: the definitive guide to measuring the extent of agreement among raters. Gaithersburg, MD: Advanced Analytics, LLC, 2014."},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.2307\/2529310"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1002\/0471722146"},{"key":"e_1_3_4_25_2","first-page":"334","article-title":"HER2-low breast cancer and response to neoadjuvant chemotherapy: a population-based cohort study","volume":"56","author":"Baez-Navarro X","year":"2024","unstructured":"Baez-Navarro X, van Bockstal MR, Jager A, et al. HER2-low breast cancer and response to neoadjuvant chemotherapy: a population-based cohort study. Pathology (Phila) 2024; 56: 334\u2013342.","journal-title":"Pathology (Phila)"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41416-024-02777-6"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41416-023-02403-x"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.clbc.2023.03.002"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.3389\/fonc.2025.1522460"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.4143\/crt.2025.761"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41379-021-00738-5"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.annonc.2025.10.019"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2514661"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1158\/1538-7445.SABCS22-GS2-03"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1158\/1538-7445.SABCS23-PO4-19-01"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2024.42.16_suppl.588"},{"key":"e_1_3_4_37_2","first-page":"882","article-title":"Improving HER2 testing reproducibility in HER2-low breast cancer","volume":"5","author":"Sajjadi E","year":"2022","unstructured":"Sajjadi E, Venetis K, Ivanova M, et al. Improving HER2 testing reproducibility in HER2-low breast cancer. Cancer Drug Resist Alhambra Calif 2022; 5: 882\u2013888.","journal-title":"Cancer Drug Resist Alhambra Calif"},{"key":"e_1_3_4_38_2","doi-asserted-by":"publisher","DOI":"10.1186\/s42047-025-00199-z"},{"key":"e_1_3_4_39_2","doi-asserted-by":"publisher","DOI":"10.1186\/s13058-023-01739-9"},{"key":"e_1_3_4_40_2","doi-asserted-by":"publisher","DOI":"10.5858\/arpa.2023-0483-CP"},{"key":"e_1_3_4_41_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0895-4356(96)00236-3"}],"container-title":["Therapeutic Advances in Medical Oncology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/17588359261451850","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/17588359261451850","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/17588359261451850","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T19:21:54Z","timestamp":1782847314000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/17588359261451850"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6]]},"references-count":40,"alternative-id":["10.1177\/17588359261451850"],"URL":"https:\/\/doi.org\/10.1177\/17588359261451850","relation":{},"ISSN":["1758-8359","1758-8359"],"issn-type":[{"value":"1758-8359","type":"print"},{"value":"1758-8359","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6]]},"article-number":"17588359261451850"}}