Impacts of HER2 immunohistochemical scores on response and outcomes of HER2-positive breast cancers after neoadjuvant therapy

Sep 29, 2026

Neoadjuvant systemic therapy is increasingly used for breast cancer overexpressing HER2, yet whether HER2 protein-expression intensity predicts treatment response and survival remains uncertain. This study assesses 197 HER2-positive patients receiving neoadjuvant therapy and definite surgery, evaluating pathological complete response, disease-free survival, and overall survival. Results link higher IHC scores with improved pCR and better DFS/OS outcomes, and multivariate analysis identifies IHC score as an independent prognostic factor.

LanguageEnglish

CategoryResearch & Report

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Introduction

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. J Chin MedAssoc Original article Impacts of HER2 immunohistochemical scores on response and outcomes of HER2-positive breast cancers after neoadjuvant therapy Yun-Ning Chiua,b,c, Chih-Yi Hsuc,d,e, Pei-Ju Liena, Ta-Chung Chaoa,c,f, Chun-Yu Liua,c,f,g, Yen-Shu Lina,b, Yu-Ling Wanga, Yi-Fang Tsaia,b,c,* , Ling-Ming Tsenga,b,c aComprehensive Breast Health Center, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; bDivision of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; cFaculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC; dDepartment of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; eCollege of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, ROC; fDivision of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; gDivision of Transfusion Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC Abstract Background: Neoadjuvant systemic therapy (NST) is conducted in increased number of patients with breast cancer overexpressing human epidermal growth factor receptor 2 (HER2) . Whether the intensity of HER2 protein expression determines response to treatment is challenged. This study aims to analyze the impact of HER2 immunohistochemical (IHC) scores on NST response and survival outcome. Methods: We analyzed a total of 197 patients with HER2-positive breast cancer receiving NST and definite surgery from a prospectively collected database. The analyzed endpoints included pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS) . More patients with IHC 2+/in situ hybridization (ISH)-positive tumors presented positive for hormonal receptors, compared with those with IHC 3+ tumors. No clinicopathological features except tumor necrosis were significantly associated with pCR. Results: Both positive hormone receptors and IHC scores stood on the borderline in statistical analysis. IHC 3+ group tends to present a higher pCR rate than IHC 2+/ISH+ groups (52 .5% vs. 34.3%) . Patients who achieved pCR had better survival outcome than that of non-pCR group. The impact of pCR on survival reached the statistical significance in the IHC 3+ group both in DFS (90 .9% vs. 76.5%; p = 0.004) and OS (97 .4% vs. 83.2%; p = 0.002) . Multivariate analysis demonstrated IHC scores as an independent predictor of survival outcome with the adjustment of tumor staging and pCR. Conclusion: HER2 IHC score is an independent predictor for outcome. IHC 3+ tumors presented a trend of higher pCR rate and better outcome in HER2-positive breast cancer patients who receive NST. Keywords: Breast neoplasm; erbB-2; Immunohistochemistry; Neoadjuvant 1. INTRODUCTION Breast cancers with overexpression and/or amplification of human epidermal growth factor receptor (HER2) account for approximately 15% to 20% of cases and are associated with aggressive phenotype and worse outcome. Treatment including chemotherapy and anti-HER2 target therapy significantly prevents recurrence and improves survival outcome.1 The success of standard treatment also reproduces in the neoadjuvant setting, *Address correspondence. Dr. Yi-Fang Tsai, Comprehensive Breast Health Center, Department of Surgery, Taipei Veterans General Hospital, 201, Section 2, Shi-Pai Road, Taipei 112, Taiwan, [ROC. E-mail: yftsai@vghtpe.gov.tw](ROC. E-mail: yftsai@vghtpe.gov.tw) (Y.-F. Tsai). Conflicts of interest: The authors declare that they have no conflicts of interest related to the subject matter or materials discussed in this article. Journal of Chinese Medical Association. (2023) 86: 409-417. Received October 7, 2022; accepted December 26, 2022. doi: 10. 1097/JCMA.0000000000000883. Copyright © 2023, the Chinese Medical Association. This is an open access article under the CC BY-NC-ND lice

FAQs

What was the main purpose of this study?

To analyze how HER2 immunohistochemical (IHC) scores relate to neoadjuvant therapy response and survival outcomes in HER2-positive breast cancer patients.

Which endpoints were used to evaluate treatment response and outcomes?

Pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS).

How did IHC score levels and pCR affect survival results?

Higher IHC (3+) tended to show a higher pCR rate than IHC 2+/ISH+ groups, and achieving pCR was associated with better DFS and OS, with statistical significance in the IHC 3+ group.

Sep 29, 2026

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