Iranian Journal of Pathology

Clinicopathological Characteristics of Breast Cancer Patients with Equivocal Immunohistochemistry: A Prevalence-Based Statistical Analysis

Document Type : Original Research

Authors

Hossein Ayatollahi 1
Amir Hossein Jafarian 2
Zahra Pakize Moghadam 1
Yasamin Ayatollahi 1
Golnaz Ghayyem Hassankhani 3
Hassan Mehrad-Majd 1

1 Cancer Molecular Pathology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

2 Pathology Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

3 Mashhad University of Medical Sciences, Mashhad, Iran

https://doi.org/10.30699/ijp.2025.2045071.3378
Abstract
Background & Objective: Although the concordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) is generally high for HER2 scores of 3+ and 1+, discrepancies remain in cases scored as IHC 2+. This study aimed to evaluate HER2/neu gene amplification using FISH in breast cancer patients with IHC 2+ and to examine associated clinicopathological characteristics.
Methods: This retrospective study included tissue samples from 369 women diagnosed with invasive ductal carcinoma of the breast and an equivocal HER2 IHC score (2+). These samples were further assessed for HER2 gene amplification using FISH. Demographic and clinicopathological data were collected and analyzed.
Results: The mean age of patients was 51.6 ± 2.6 years. FISH analysis revealed no HER2 amplification in 72.6% of IHC 2+ cases, while 27.4% demonstrated amplification. HER2 amplification was significantly associated with younger age, higher histological grade, lymph node involvement, larger tumor size, and reduced survival rate. No significant association was observed between HER2 amplification and margin involvement.
Conclusion: HER2 amplification is a significant predictor of aggressive tumor behavior and may necessitate targeted therapy. In cases with IHC 2+, both FISH results and relevant clinicopathological features should be considered prior to initiating trastuzumab treatment.

Keywords

Breast Neoplasms
HER2
In Situ Hybridization
Immunohistochemistry

Subjects

Copyright © 2025. This is an open-access article distributed under the terms of the Creative Commons Attribution- 4.0 International License which permits Share, copy and redistribution of the material in any medium or format or adapt, remix, transform, and build upon the material for any purpose, even commercially.

  1. Sun YS, Zhao Z, Yang ZN, Xu F, Lu HJ, Zhu ZY, et al. Risk Factors and Preventions of Breast Cancer. Int J Biol Sci. 2017;13(11):1387-97. [DOI:10.7150/ijbs.21635] [PMID] [PMCID]
  2. Arnold M, Morgan E, Rumgay H, Mafra A, Singh D, Laversanne M, et al. Current and future burden of breast cancer: Global statistics for 2020 and 2040. Breast. 2022;66:15-23. [DOI:10.1016/j.breast.2022.08.010] [PMID] [PMCID]
  3. Ross JS, Fletcher JA, Linette GP, Stec J, Clark E, Ayers M, et al. The HER-2/ neu Gene and Protein in Breast Cancer 2003: Biomarker and Target of Therapy. Oncologist. 2003;8(4):307-25. [DOI:10.1634/theoncologist.8-4-307] [PMID]
  4. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, Goldhirsch A, Untch M, Smith I, et al. Trastuzumab after Adjuvant Chemotherapy in HER2-Positive Breast Cancer. N Engl J Med. 2005;353(16):1659-72. [DOI:10.1056/NEJMoa052306] [PMID]
  5. Lower EE, Glass E, Blau R, Harman S. HER-2/neu expression in primary and metastatic breast cancer. Breast Cancer Res Treat. 2009;113(2):301-6. [DOI:10.1007/s10549-008-9931-6] [PMID]
  6. Slamon D, Eiermann W, Robert N, Pienkowski T, Martin M, Press M, et al. Adjuvant Trastuzumab in HER2-Positive Breast Cancer. N Engl J Med. 2011; 365(14):1273-83. [DOI:10.1056/NEJMoa0910383] [PMID] [PMCID]
  7. Bartsch R, Wenzel C, Steger GG. Trastuzumab in the management of early and advanced stage breast cancer. Biologics. 2007 Mar;1(1):19-31.
  8. Cuadros M, Villegas R. Systematic Review of HER2 Breast Cancer Testing. Appl Immunohistochem Mol Morphol. 2009;17(1):1-7. [DOI:10.1097/PAI.0b013e318169fc1c] [PMID]
  9. Zhang H, Ren G, Wang X, Zhao J, Yao H, Bai Y, et al. HER-2 gene amplification by fluorescence in situ hybridization (FISH) compared with immunohistochemistry (IHC) in breast cancer: a study of 528 equivocal cases. Breast Cancer Res Treat. 2012;134(2):743-9. [DOI:10.1007/s10549-012-2101-x] [PMID]
  10. Chivukula M, Bhargava R, Brufsky A, Surti U, Dabbs DJ. Clinical importance of HER2 immunohistologic heterogeneous expression in core-needle biopsies vs resection specimens for equivocal (immunohistochemical score 2+) cases. Modern Pathology. 2008;21(4):363-8. [DOI:10.1038/modpathol.3801021] [PMID]
  11. Wesoła M, Jeleń M. A Comparison of IHC and FISH Cytogenetic Methods in the Evaluation of HER2 Status in Breast Cancer. Adv Clin Exp Med. 2015;24(5):899-904. [DOI:10.17219/acem/27923] [PMID]
  12. Bogdanovska-Todorovska M, Kostadinova-Kunovska S, Jovanovik R, Krsteska B, Kondov G, Kondov B, et al. Correlation of Immunohistochemistry and Fluorescence in Situ Hybridization for HER-2 Assessment in Breast Cancer Patients: Single Centre Experience. Open Access Maced J Med Sci. 2018;6(4):593-9. [DOI:10.3889/oamjms.2018.124] [PMID] [PMCID]
  13. Efared B, Sidibé IS, Gamrani S, El Otmani I, Erregad F, Hammas N, et al. The Assessment of HER2 Gene Status by Fluorescence In Situ Hybridization in Invasive Breast Carcinomas With Equivocal HER2 Immunostaining: Experience From a Single Institution. Int J Surg Pathol. 2018 Oct 9;26(7):593-9. [DOI:10.1177/1066896918767546] [PMID]
  14. Mostafa NAE, Eissa SS, Belal DM, Shoman SH. Assessment of Her-2/neu gene amplification status in breast carcinoma with equivocal 2+ Her-2/neu immunostaining. J Egypt Natl Canc Inst. 2011 Mar;23(1):41-6. [DOI:10.1016/j.jnci.2011.07.006] [PMID]
  15. Al-Zadjali Y, Al-Rashdi A, Al-Husaini S, Al-Badi S, Al-Badi H, Arafa M. Clinicopathological Study of Breast Carcinoma Patients with Equivocal HER2 Immunohistochemical Status: Five-Year Experience from a Tertiary Care Center. Maedica - A Journal of Clinical Medicine. 2023;18(1). [DOI:10.26574/maedica.2023.18.1.27] [PMCID]
  16. Ji Y, Sheng L, Du X, Qiu G, Chen B, Wang X. Clinicopathological variables predicting HER-2 gene status in immunohistochemistry-equivocal (2+) invasive breast cancer. J Thorac Dis. 2014;6(7):896-904.
  17. Panjwani P, Epari S, Karpate A, Shirsat H, Rajsekharan P, Basak R, et al. Assessment of HER-2/neu status in breast cancer using fluorescence in situ hybridization & immunohistochemistry: Experience of a tertiary cancer referral centre in India. Indian J Med Res. 2010;132:287-94.
  18. Patil Okaly G, Panwar D, Lingappa K, Kumari P, Anand A, Kumar P, et al. FISH and HER2/neu equivocal immunohistochemistry in breast carcinoma. Indian J Cancer. 2019;56(2):119. [DOI:10.4103/ijc.IJC_333_18] [PMID]
  19. Zhao B, Wang Y, Xu H. Concordance of immunohistochemistry and fluorescence in situ hybridization for assessment of HER2 status in breast cancer patients in Xinjiang autonomous region, China. Int J Clin Exp Pathol. 2017;10(10):10459-66.
  20. Ménard S, Fortis S, Castiglioni F, Agresti R, Balsari A. HER2 as a Prognostic Factor in Breast Cancer. Oncology. 2001;61(Suppl. 2):67-72. [DOI:10.1159/000055404] [PMID]
  21. Anders CK, Hsu DS, Broadwater G, Acharya CR, Foekens JA, Zhang Y, et al. Young Age at Diagnosis Correlates With Worse Prognosis and Defines a Subset of Breast Cancers With Shared Patterns of Gene Expression. J Clin Oncol. 2008; 26(20):3324-30. [DOI:10.1200/JCO.2007.14.2471] [PMID]
  22. Liedtke C, Rody A, Gluz O, Baumann K, Beyer D, Kohls EB, et al. The prognostic impact of age in different molecular subtypes of breast cancer. Breast Cancer Res Treat. 2015;152(3):667-73. [DOI:10.1007/s10549-015-3491-3] [PMID]
  23. Cheng X. A Comprehensive Review of HER2 in Cancer Biology and Therapeutics. Genes (Basel). 2024;15(7). [DOI:10.3390/genes15070903] [PMID] [PMCID]
  24. Takada K, Kashiwagi S, Asano Y, Goto W, Morisaki T, Shibutani M, et al. Differences in tumor-infiltrating lymphocyte density and prognostic factors for breast cancer by patient age. World J Surg Oncol. 2022;20(1):38. [DOI:10.1186/s12957-022-02513-5] [PMID] []
  25. Englander K, Chintapally N, Gallagher J, Elleson K, Sun W, Whiting J, et al. Factors Influencing Lymph Node Positivity in HER2/neu+ Breast Cancer Patients. Curr Oncol. 2023;30(3):2825-33. [DOI:10.3390/curroncol30030215] [PMID] [PMCID]
  26. JIBIKI N, NAKAZAWA T, NOGAMI M, YOSHIDA K, HASEGAWA A, GUO F, et al. Prognostic Evaluation of HER2-positive Early Breast Cancers Using Clinico-pathological Criteria. Cancer Diagnosis & Prognosis. 2024;4(3):326-32. [DOI:10.21873/cdp.10328] [PMID] [PMCID]
  27. Tong ZJ, Shi NY, Zhang ZJ, Yuan XD, Hong XM. Expression and prognostic value of HER-2/neu in primary breast cancer with sentinel lymph node metastasis. Biosci Rep. 2017;37(4). [DOI:10.1042/BSR20170121] [PMID] [PMCID]
  28. Ayadi L, Khabir A, Amouri H, Karray S, Dammak A, Guermazi M, et al. Correlation of HER-2 over-expression with clinico-pathological parameters in Tunisian breast carcinoma. World J Surg Oncol. 2008 Oct;6:112. [DOI:10.1186/1477-7819-6-112] [PMID] [PMCID]
  29. Slamon DJ, Clark GM, Wong SG, Levin WJ, Ullrich A, McGuire WL. Human Breast Cancer: Correlation of Relapse and Survival with Amplification of the HER-2/ neu Oncogene. Science (1979). 1987;235(4785):177-82. [DOI:10.1126/science.3798106] [PMID]
  30. Laughner E, Taghavi P, Chiles K, Mahon PC, Semenza GL. HER2 (neu) Signaling Increases the Rate of Hypoxia-Inducible Factor 1α (HIF-1α) Synthesis: Novel Mechanism for HIF-1-Mediated Vascular Endothelial Growth Factor Expression. Mol Cell Biol. 2001;21(12):3995-4004. [PMID] [PMCID] [DOI:10.1128/MCB.21.12.3995-4004.2001]
  31. Schoppmann SF, Tamandl D, Roberts L, Jomrich G, Schoppmann A, Zwrtek R, et al. HER2/neu expression correlates with vascular endothelial growth factor-C and lymphangiogenesis in lymph node-positive breast cancer. Annals of Oncology. 2010;21(5):955-60. [DOI:10.1093/annonc/mdp532] [PMID]
  32. K S, Arumugam M, Shetty J, Shetty R, Asnani R, Shetty P. Breast Carcinoma - A Comparative Study of Immunohistochemistry and Fluorescence in Situ Hybridization for Her-2 Assessment and Association of ER, PR, HER-2 and Ki-67 Expression with Clinico-Pathological Parameters. Iran J Pathol. 2022;17(4):435-42. [DOI:10.30699/ijp.2022.538167.2712] [PMID] [PMCID]
  33. Yoshihara E, Smeets A, Laenen A, Reynders A, Soens J, Van Ongeval C, et al. Predictors of axillary lymph node metastases in early breast cancer and their applicability in clinical practice. The Breast. 2013;22(3):357-61. [DOI:10.1016/j.breast.2012.09.003] [PMID]
  34. Miricescu D, Totan A, Stanescu-Spinu II, Badoiu SC, Stefani C, Greabu M. PI3K/AKT/mTOR Signaling Pathway in Breast Cancer: From Molecular Landscape to Clinical Aspects. Int J Mol Sci. 2020;22(1). [DOI:10.3390/ijms22010173] [PMID] [PMCID]
  35. Xu R, Perle MA, Inghirami G, Chan W, Delgado Y, Feiner H. Amplification of Her-2/neu Gene in Her-2/neu-Overexpressing and -Nonexpressing Breast Carcinomas and Their Synchronous Benign, Premalignant, and Metastatic Lesions Detected by FISH in Archival Material. Modern Pathology. 2002;15(2):116-24. [DOI:10.1038/modpathol.3880503] [PMID]
  36. Dieci MV, Barbieri E, Bettelli S, Piacentini F, Omarini C, Ficarra G, et al. Predictors of human epidermal growth factor receptor 2 fluorescence in-situ hybridisation amplification in immunohistochemistry score 2+ infiltrating breast cancer: a single institution analysis. J Clin Pathol. 2012;65(6):503-6. [DOI:10.1136/jclinpath-2011-200643] [PMID]
  37. Zhang Y, Wu J, Huang W, Wang Y, Rivera Galvis L, Chen T, et al. Pathologic evaluation of lumpectomy resection margins for invasive breast cancer: a single institution's experience. Int J Clin Exp Pathol. 2023; 16(2):40-7.
  38. Miller AR, Brandao G, Prihoda TJ, Hill C, Cruz AB, Yeh I. Positive margins following surgical resection of breast carcinoma: Analysis of pathologic correlates. J Surg Oncol. 2004;86(3):134-40. [DOI:10.1002/jso.20059] [PMID]
  39. Bergeron A, Bertaut A, Beltjens F, Charon-Barra C, Amet A, Jankowski C, et al. Anticipating changes in the HER2 status of breast tumours with disease progression-towards better treatment decisions in the new era of HER2-low breast cancers. Br J Cancer. 2023;129(1):122-34. [DOI:10.1038/s41416-023-02287-x] [PMID] [PMCID]
  40. Ahmed ARH. HER2 expression is a strong independent predictor of nodal metastasis in breast cancer. J Egypt Natl Canc Inst. 2016;28(4):219-27. [DOI:10.1016/j.jnci.2016.09.002] [PMID]
Iranian Journal of Pathology
Volume 20, Issue 3
Summer 2025
Pages 273-279

  • Receive Date 24 January 2025
  • Revise Date 04 March 2025
  • Accept Date 11 March 2025

Home

Guide for Authors

Submit Manuscript

Contact Us