LEADER 04486nab a2200613 i 4500
001 publ39214
005 20260218085325.0
008 260218s2026 hu o 000 eng d
022 |a 0893-3952 
024 7 |a 10.1016/j.modpat.2025.100925  |2 doi 
024 7 |a 36410193  |2 mtmt 
040 |a SZTE Publicatio Repozitórium  |b hun 
041 |a eng 
100 1 |a Rakha Emad A. 
245 1 0 |a International Expert Consensus Recommendations for HER2 Reporting in Breast Cancer   |h [elektronikus dokumentum] :  |b Focus on HER2-low and Ultralow Categories /  |c  Rakha Emad A. 
260 |c 2026 
300 |a 14 
490 0 |a MODERN PATHOLOGY  |v 39 No. 1 
520 3 |a The concept of "HER2-negative" breast cancer is evolving, with the recognition of HER2-low and HER2-ultralow subsets. These subsets are clinically relevant regarding treatment with the antibody-drug conjugate trastuzumab deruxtecan (T-DXd), which has shown survival benefit in patients with metastatic carcinoma with minimal HER2 protein expression that lack HER2 gene amplification by in situ hybridisation (ISH). In clinical trials using T-DXd, HER2-low was defined as immunohistochemistry (IHC) score 1+ or IHC score 2+ without HER2 gene amplification. HER2-ultralow was defined as faint or barely perceptible, incomplete membrane staining in >0 to ≤10% of tumour cells (IHC score 0+/with membrane staining) and HER2-null as complete absence of staining (IHC score 0/absent membrane staining). These results now necessitate more detailed evaluation and reporting of traditional "HER2-negative" results to identify patients with metastatic breast cancer who may benefit from T-DXd therapy. Both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have extended regulatory approval of T-DXd to patients with metastatic breast cancer showing HER2-low or HER2-ultralow expression. Updated clinical management guidelines now, therefore, incorporate the spectrum of HER2 results into treatment selection algorithms in the metastatic setting. To align histopathologic practice with these developments, the College of American Pathologists (CAP) has issued a new biomarker-reporting template that recommends explicit distinction between IHC 0/absent membrane staining and IHC 0+/with membrane staining. Key concerns among pathologists include assay variability, scoring reproducibility and quality assurance standards for accurately detecting such low levels of HER2 expression. This manuscript provides expert consensus, evidence-based practical recommendations for identifying and reporting tumours with HER2-low and HER2-ultralow expression. We emphasise standardised testing protocols, validated assays, robust internal and external controls, and focused training for pathologists. A universal structured pathology report is proposed to highlight the accurate distinction between IHC 0 (null), IHC 0+ (ultralow), and HER2-low expression. 
650 4 |a Klinikai orvostan 
700 0 1 |a Tan Puay Hoon  |e aut 
700 0 2 |a Van Bockstal Mieke R.  |e aut 
700 0 2 |a Allison Kimberly H.  |e aut 
700 0 2 |a Brogi Edi  |e aut 
700 0 2 |a Callagy Grace  |e aut 
700 0 2 |a Cserni Gábor  |e aut 
700 0 2 |a Jaffer Shabnam  |e aut 
700 0 2 |a Foschini Maria Pia  |e aut 
700 0 2 |a Gobbi Helenice  |e aut 
700 0 2 |a Kulka Janina  |e aut 
700 0 2 |a Li Xiaoxian  |e aut 
700 0 2 |a Provenzano Elena  |e aut 
700 0 2 |a Shaaban Abeer M.  |e aut 
700 0 2 |a Tse Gary M.  |e aut 
700 0 2 |a Varga Zsuzsanna  |e aut 
700 0 2 |a Vincent-Salomon Anne  |e aut 
700 0 2 |a Yamaguchi Rin  |e aut 
700 0 2 |a Yang Wentao  |e aut 
700 0 2 |a ElSheikh Soha  |e aut 
700 0 2 |a Bhargava Rohit  |e aut 
700 0 2 |a De Brot Marina  |e aut 
700 0 2 |a Canas-Marques Rita  |e aut 
700 0 2 |a Marchiò Caterina  |e aut 
700 0 2 |a Warren Madhuri V  |e aut 
700 0 2 |a van Deurzen Carolien H M  |e aut 
700 0 2 |a Mir Yasmeen  |e aut 
700 0 2 |a Deb Rahul  |e aut 
700 0 2 |a Wen Hannah  |e aut 
700 0 2 |a Ellis Ian O.  |e aut 
700 0 2 |a Kollaborációs szervezet: UK National Coordinating Committee of Breast Pathology  |e aut 
700 0 2 |a Kollaborációs szervezet: Association of Breast Pathology  |e aut 
700 0 2 |a Kollaborációs szervezet: European Working Group for Breast Screening Pathology  |e aut 
700 0 2 |a Kollaborációs szervezet: International Society of Breast Pathology  |e aut 
856 4 0 |u http://publicatio.bibl.u-szeged.hu/39214/1/ModPathol-2026-39-100925-HER2low-Rakha.pdf  |z Dokumentum-elérés