This Article Full Text (PDF) All Versions of this Article: theoncologist.2008-0184v1 13/11/1134    most recent eLetters: Submit a response to this article Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services E-mail this article link to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints/Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Allred, D. C. Search for Related Content PubMed PubMed Citation Articles by Allred, D. C.

Breast Cancer

Commentary: Hormone Receptor Testing in Breast Cancer: A Distress Signal from Canada

Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA

Correspondence: D. Craig Allred, M.D., Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8118, St. Louis, Missouri 63110, USA. Telephone: 314-362-6313; Fax: 314-747-2663; e-mail: dcallred{at}path.wustl.edu

Received August 21, 2008; accepted for publication September 4, 2008; first published online in THE ONCOLOGIST Express on November 5, 2008.

Disclosure: Employment/leadership position: None; Intellectual property rights/inventor/patent holder: None; Consultant/advisory role: D. Craig Allred, Genomic Health Clinic, DAKO, Pfizer; Honoraria: None; Research funding/contracted research: D. Craig Allred, Pfizer; Ownership interest: D. Craig Allred, Scientific Advisory Board of Clarient, Inc.; Expert testimony: None; Other: None.

The content of this article has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from commercial bias. No financial relationships relevant to the content of this article have been disclosed by the authors, planners, independent peer reviewers, or staff managers.

Recent events in Canada underscore substantial problems with estrogen receptor (ER) testing by immunohistochemistry (IHC) in breast cancer [1, 2]. In 2005, a woman there was diagnosed with invasive lobular carcinoma. Her tumor was tested for ER expression by IHC in a laboratory managed by Eastern Health, the provincial health care provider in Newfoundland and Labrador. The results were negative, which is unusual for this type of tumor, so her physicians had it retested in another laboratory. The new IHC results came back positive, and the discrepancy led Eastern Health to investigate the accuracy of testing in Newfoundland and Labrador. Eventually, over 2,000 originally ER-negative cases were retested in another laboratory in Ontario, and nearly 40% were found to be ER-positive. An official inquiry was convened in July 2007, to determine the scope and causes of the problem, and to develop policies to prevent it from happening in the future (Commission of Inquiry on Hormone Receptor Testing at http://www.cihrt.nl.ca/transcripts.html). The conclusions of this inquiry are still forthcoming.

In current clinical practice, ER testing is mandatory in all newly diagnosed breast cancers, and accurate results are critical in determining the use of adjuvant hormonal therapy. This type of therapy significantly improves the outcome of many patients with ER-positive tumors, but it is ineffective with ER-negative disease. For this reason, most of the erroneous ER-negative patients in Newfoundland and Labrador were not treated with hormonal therapy, and some were almost certainly harmed because of it. This tragic outcome was avoidable and raises several urgent questions that should concern all of us: How did it happen? Is it happening elsewhere? What is being done to prevent it?

There are many well-known problems associated with measuring proteins by IHC, particularly proteins requiring quantified results such as ER [3, 4]. Some problems involve preanalytical issues unrelated to IHC itself, such as delayed or inadequate fixation of tissue, allowing proteins to degrade. Others are analytical in nature, such as the use of diverse reagents with unequal sensitivities [5–8], or antigen-retrieval procedures that inadequately re-expose proteins masked during fixation [4]. Most IHC assays rely on enzymatic detection systems with very rapid kinetics that are difficult to control, and it is very challenging to quantify results in an accurate and reproducible manner [9]. Postanalytical events may also contribute in the sense that tumors with very low levels of receptors (e.g., 1%–10% positive cells) may respond to hormonal therapy [6, 7, 10], and some laboratories use arbitrary definitions of positive that are too high (e.g., >10% positive cells). Fastidious oversight by highly experienced and knowledgeable personnel is required to recognize, resolve, and avoid these problems, and some or all of them may have contributed to the debacle in Canada.

Unfortunately, the problem with ER testing by IHC is not restricted to Newfoundland and Labrador. Perhaps the best evidence for this comes from the United Kingdom National External Quality Assessment Service (NEQAS). This organization has conducted and published the results of several studies on the accuracy and reproducibility of evaluating ER by IHC based on proficiency testing of 150 laboratories in 26 countries worldwide [4, 11–14]. The results identified error rates in some laboratories rivaling those in Newfoundland and Labrador, as well as the major technical problems causing them. The U.S. does not participate in NEQAS, and information regarding the accuracy of ER testing in this country is hard to find. Although many laboratories in the U.S. participate in proficiency testing offered by the College of American Pathologists (CAP), many do not, and the evaluation of ER by the CAP is less comprehensive than that of the NEQAS, so detailed results are not available. However, there is compelling anecdotal evidence suggesting that problems in the U.S. are also substantial. For example, in a recent large international clinical trial comparing hormonal therapies in receptor-positive breast cancer, a subset of >100 patients was enrolled with ER-negative/progesterone receptor (PgR)-positive tumors based on local laboratory results from several countries, including the U.S., who was a major contributor to the trial [15]. Repeat testing in an expert central laboratory revealed a 69% false-negative rate for ER in this subset of patients. Furthermore, there was a 44% false-negative rate for PgR in the group of >1,200 ER-positive/PgR-negative patients enrolled based on local laboratory results, so the problem is larger than ER alone. While far from being scientific, the false-negative rate of IHC testing for both receptors in my consulting practice over the past 10 years is about 30%, which is similar to that of other experienced consulting pathologists I have spoken with on this issue.

Given the critical need for accurate ER and PgR results in all patients with breast cancer, and the widespread difficulty obtaining them, it is clear that something must be done to remedy the problem. On one hand, it should be relatively easy to resolve because several comprehensively validated IHC methods have been published for other laboratories to emulate [5–7, 10, 16, 17]. On the other hand, it is remarkably difficult to persuade laboratories on a global scale to adopt the same methods, or to rigorously standardize and validate their own. A few years ago, a similar widely publicized predicament regarding human epidermal growth factor receptor (HER)-2 testing in breast cancer led to the development of rigorous guidelines by the CAP and the American Society of Clinical Oncology (ASCO) [18], and laboratories in the U.S. must soon comply with these guidelines to maintain CAP accreditation. The CAP and ASCO are also aware of the need to improve ER and PgR testing, and they are in the process of developing enforceable guidelines for these biomarkers as well. However, CAP accreditation is currently not required in the U.S. for laboratories to conduct these tests, and most laboratories are not CAP accredited. The situation is similar in other countries and it will take considerable resources, education, and persistence to achieve universal compliance in the use of assays that are comprehensively standardized and validated in an equivalent manner.

Ultimately, however, it is unrealistic to expect that even perfect tests for ER and PgR alone, by IHC or any other methods, will be sufficiently powerful to predict the response of all breast cancer patients to hormonal therapy because the biology involved is so complex. New more powerful predictors are needed, and they will most likely be based on multiple biomarkers. In this regard, there are many promising new approaches on the horizon at varying stages of development and validation, including oncotype DX® (Genomic Health, Inc., Redwood City, CA, http://www.genomichealth.com) [19, 20], the HOXB13/IL17BR gene ratio [21–23], and estrogen-regulated gene signatures determined by microarrays [24], to name a few. Hopefully, these and other approaches will lead to significant improvements in predicting response to hormonal therapies, and it will be important for them to avoid making the same mistakes concerning proficiency and standardization that have plagued ER, PgR, and HER-2 testing by IHC.

	REFERENCES

Top References

 

1. Hede K. Breast cancer testing scandal shines spotlight on black box of clinical laboratory testing. J Natl Cancer Inst 2008;100:836–837, 844.[Free Full Text]
2. Mathews AW. Bad cancer tests drawing scrutiny. The Wall Street Journal. B1–B2; January 4, 2008.
3. Allred DC, Mohsin SK. ER expression is not bimodal in breast cancer. Am J Clin Pathol 2005;124:474–475; author reply 475–476.[Medline]
4. Rhodes A, Jasani B, Balaton AJ et al. Immunohistochemical demonstration of oestrogen and progesterone receptors: Correlation of standards achieved on in house tumours with that achieved on external quality assessment material in over 150 laboratories from 26 countries. J Clin Pathol 2000;53:292–301.[Abstract/Free Full Text]
5. Cheang MC, Treaba DO, Speers CH et al. Immunohistochemical detection using the new rabbit monoclonal antibody SP1 of estrogen receptor in breast cancer is superior to mouse monoclonal antibody 1D5 in predicting survival. J Clin Oncol 2006;24:5637–5644.[Abstract/Free Full Text]
6. Harvey JM, Clark GM, Osborne CK et al. Estrogen receptor status by immunohistochemistry is superior to the ligand-binding assay for predicting response to adjuvant endocrine therapy in breast cancer. J Clin Oncol 1999;17:1474–1481.[Abstract/Free Full Text]
7. Mohsin SK, Weiss H, Havighurst T et al. Progesterone receptor by immunohistochemistry and clinical outcome in breast cancer: A validation study. Mod Pathol 2004;17:1545–1554.[CrossRef][Medline]
8. Press M, Spaulding B, Groshen S et al. Comparison of different antibodies for detection of progesterone receptor in breast cancer. Steroids 2002;67:799–813.[CrossRef][Medline]
9. Chung GG, Zerkowski MP, Ghosh S et al. Quantitative analysis of estrogen receptor heterogeneity in breast cancer. Lab Invest 2007;87:662–669.[CrossRef][Medline]
10. Love RR, Duc NB, Allred DC et al. Oophorectomy and tamoxifen adjuvant therapy in premenopausal Vietnamese and Chinese women with operable breast cancer. J Clin Oncol 2002;20:2559–2566.[Abstract/Free Full Text]
11. Leake R, Barnes D, Pinder S et al. Immunohistochemical detection of steroid receptors in breast cancer: A working protocol. UK Receptor Group, UK NEQAS, The Scottish Breast Cancer Pathology Group, and The Receptor and Biomarker Study Group of the EORTC. J Clin Pathol 2000;53:634–635.[Abstract/Free Full Text]
12. Rhodes A, Jasani B, Balaton AJ et al. Study of interlaboratory reliability and reproducibility of estrogen and progesterone receptor assays in Europe. Documentation of poor reliability and identification of insufficient microwave antigen retrieval time as a major contributory element of unreliable assays. Am J Clin Pathol 2001;115:44–58.[Abstract/Free Full Text]
13. Rhodes A, Jasani B, Balaton AJ et al. Frequency of oestrogen and progesterone receptor positivity by immunohistochemical analysis in 7016 breast carcinomas: Correlation with patient age, assay sensitivity, threshold value, and mammographic screening. J Clin Pathol 2000;53:688–696.[Abstract/Free Full Text]
14. Rhodes A, Jasani B, Barnes DM et al. Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: Interlaboratory variance in the sensitivity of detection and evaluation of scoring systems. J Clin Pathol 2000;53:125–130.[Abstract/Free Full Text]
15. Viale G, Regan MM, Maiorano E et al. Prognostic and predictive value of centrally reviewed expression of estrogen and progesterone receptors in a randomized trial comparing letrozole and tamoxifen adjuvant therapy for postmenopausal early breast cancer: BIG 1–98. J Clin Oncol 2007;25:3846–3852.[Abstract/Free Full Text]
16. Barnes DM, Harris WH, Smith P et al. Immunohistochemical determination of oestrogen receptor: Comparison of different methods of assessment of staining and correlation with clinical outcome of breast cancer patients. Br J Cancer 1996;74:1445–1451.[Medline]
17. Phillips T, Murray G, Wakamiya K et al. Development of standard estrogen and progesterone receptor immunohistochemical assays for selection of patients for antihormonal therapy. Appl Immunohistochem Mol Morphol 2007;15:325–331.[CrossRef][Medline]
18. Wolff AC, Hammond ME, Schwartz JN et al. American Society of Clinical Oncology/College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 testing in breast cancer. J Clin Oncol 2007;25:118–145.[Abstract/Free Full Text]
19. Paik S, Shak S, Tang G et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med 2004;351:2817–2826.[Abstract/Free Full Text]
20. Paik S, Tang G, Shak S et al. Gene expression and benefit of chemotherapy in women with node-negative, estrogen receptor-positive breast cancer. J Clin Oncol 2006;24:3726–3734.[Abstract/Free Full Text]
21. Goetz MP, Suman VJ, Ingle JN et al. A two-gene expression ratio of homeobox 13 and interleukin-17B receptor for prediction of recurrence and survival in women receiving adjuvant tamoxifen. Clin Cancer Res 2006;12:2080–2087.[Abstract/Free Full Text]
22. Ma XJ, Hilsenbeck SG, Wang W et al. The HOXB13:IL17BR expression index is a prognostic factor in early-stage breast cancer. J Clin Oncol 2006;24:4611–4619.[Abstract/Free Full Text]
23. Ma XJ, Wang Z, Ryan PD et al. A two-gene expression ratio predicts clinical outcome in breast cancer patients treated with tamoxifen. Cancer Cell 2004;5:607–616.[CrossRef][Medline]
24. Oh DS, Troester MA, Usary J et al. Estrogen-regulated genes predict survival in hormone receptor-positive breast cancers. J Clin Oncol 2006;24:1656–1664.[Abstract/Free Full Text]

This article has been cited by other articles:

				P. Roepman, H. M. Horlings, O. Krijgsman, M. Kok, J. M. Bueno-de-Mesquita, R. Bender, S. C. Linn, A. M. Glas, and M. J. van de Vijver Microarray-Based Determination of Estrogen Receptor, Progesterone Receptor, and HER2 Receptor Status in Breast Cancer Clin. Cancer Res., November 15, 2009; 15(22): 7003 - 7011. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) All Versions of this Article: theoncologist.2008-0184v1 13/11/1134    most recent eLetters: Submit a response to this article Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services E-mail this article link to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints/Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Allred, D. C. Search for Related Content PubMed PubMed Citation Articles by Allred, D. C.