At a Glance
Why Get Tested?
When to Get Tested?
Test Preparation Needed?
The Test Sample
What is being tested?
Her-2/neu is an oncogene. It is a gene that codes for a protein that is a receptor for a particular growth factor that promotes cell growth. Normal epithelial cells found throughout the body contain two copies of the Her-2/neu gene and produce low levels of the Her-2/neu protein on the surface of their cells. In about 20-30% of invasive breast cancers (and some other cancers, such as ovarian and bladder cancer), the Her-2/neu gene is amplified and its protein is over-expressed. Tumors that have this over-expression tend to grow more aggressively and resist endocrine (anti-hormone) therapy and some chemotherapies. People with Her-2/neu positive breast cancers tend to have a poorer prognosis, but this tumor characteristic also makes them candidates to receive treatment specific for Her-2/neu-positive cancers.
To determine if a tumor is positive for Her-2/neu, a biopsy is taken and the sample of tumor is tested. There are two main ways to test Her-2/neu status: immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH). IHC measures the amount of Her-2/neu protein present. FISH looks at the genetic level for actual gene amplification – the number of copies of the gene present. IHC is currently the most widely used initial testing method; however, if it is indeterminate or negative, then the FISH method is often done as a follow-up test.
A Her2/neu test blood test is also available. The amount of Her-2/neu protein present in the serum is loosely associated with the amount of Her-2/neu -positive cancer present. This test is not used for screening purposes and is not a substitute for tissue testing but may be ordered to help assess a person's prognosis and to monitor the effectiveness of treatment. After an initial diagnosis of metastatic breast cancer is made, this blood test may be performed and, if the initial level is greater than 15 ng/mL, then the test may be used to monitor treatment.
How is the sample collected for testing?
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 200-202.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 548-551.
Hicks, D. and Kulkarni, S. (2008 April 14). HER2+ Breast Cancer: Review of Biologic Relevance and Optimal Use of Diagnostic Tools. Medscape from American Journal of Clinical Pathology [On-line information]. Available online at http://www.medscape.com/viewarticle/570732 through http://www.medscape.com. Accessed July 2009.
Markman, M. (2009 June 30, Updated). Breast Cancer and HER2. Emedicine [On-line information]. Available online at http://emedicine.medscape.com/article/1689966-overview through http://emedicine.medscape.com. Accessed July 2009.
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(2008 December 02). NCCN Clinical Practice Guidelines in Oncology, Breast Cancer v.1.2009 Medscape from National Comprehensive Cancer Network [On-line information]. PDF available for download at http://misc.medscape.com/images/586/406/Breast-Medscape.pdf through http://misc.medscape.com. Accessed July 2009.
(2006 December). What to Know: ASCO's Guideline on HER2 Testing for Breast Cancer. American Society of Clinical Oncologists [On-line information]. Available online through http://www.cancer.net. Accessed July 2009.
Esteva, F. et. al. (2005 May 13). Clinical Utility of Serum HER2/neu in Monitoring and Prediction of Progression-Free Survival in Metastatic Breast Cancer Patients Treated With Trastuzumab-Based Therapies. Medscape from Breast Cancer Research [On-line information]. Available online at http://www.medscape.com/viewarticle/503103 through http://www.medscape.com. Accessed July 2009.
Tse, C. et. al. (2005). Evaluation of the Quantitative Analytical Methods Real-Time PCR for HER-2 Gene Quantification and ELISA of Serum HER-2 Protein and Comparison with Fluorescence in Situ Hybridization and Immunohistochemistry for Determining HER-2 Status in Breast Cancer Patients. Clinical Chemistry. 2005;51:1093-1101 [On-line information]. Available online at http://www.clinchem.org/cgi/reprint/51/7/1093 through http://www.clinchem.org. Accessed July 2009.
Zidan J, Dashkovsky I, Stayerman C, et al. Comparison of HER-2 overexpression in primary breast cancer and metastatic sites and its effect on biological targeting therapy of metastatic disease. Br J Cancer. 2005 Sep 5;93(5):552-6.
Lower EE, Glass E, Blau R, Harman S. HER-2/neu expression in primary and metastatic breast cancer. 1: Breast Cancer Res Treat. 2009 Jan;113(2):301-6. Epub 2008 Feb 14.
Carney WP, Brown-Shimer S, Hamer PJ. Serum HER-2/neu testing can identify HER-2/neu positive patients previously classified as negative by tissue testing. American Association for Clinical Chemistry Annual Meeting Proceedings, 2008. Clin Chem Vol 54(56) Suppl, Pg A130: Abstract No. C-96.
Schwartz MK, et al. International Journal of Biological Markers 2000;15(4):324.
Lipton A, et al. Journal of Clinical Oncology 2002;20(6):1467.
Esteva FJ, et al. Journal of Clinical Oncology 2002;20(7):1800.
Lipton et al. Serial Serum HER2/neu Levels and Clinical Response Status for Study EGF20009 - Metastatic Breast Cancer, Sept 7th 2007, ASCO Breast Cancer Meeting, San Francisco.
Serum HER-2/neu and Relative Resistance to TRASTUZUMAB-based Therapy in Patients With Metastatic Breast Cancer. Cancer 2008; 113:1294-1301.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
Check, W. (2002 February). Making the call on HER2 testing methods. CAP Today, In the News [On-line journal]. Available online at http://www.cap.org/html/publications/feature.html through http://www.cap.org.
Check, W. (2002 February). Serum HER2 testing. CAP Today, In the News [On-line journal]. Available online at http://www.cap.org/html/publications/sidebar1.html through http://www.cap.org.
ASCO (1996). c-erbB-2 as a Marker for Breast Cancer. American Society for Clinical Oncology [On-line guideline]. Available online at http://www.asco.org/prof/pp/html/guide/tumor/m_tumor14.htm through http://www.asco.org.
ACS (2001). Immunotherapy with Trastuzumab (Herceptin). American Cancer Society [On-line information]. Available online through http://www.cancer.org.
ACS (2001). How is Breast Cancer Diagnosed? American Cancer Society, Cancer Reference Information [On-line information]. Available online through http://www.cancer.org.
Locke, J. (2001 February). HER2/neu Testing. American Association for Clinical Chemistry, Strategies [Newsletter]. Available through AACC (http://www.aacc.org)
Yazifi, H., and Gown, A. (2002 June). Controversies and guidelines in tissue-based HER-2/neu testing in breast cancer. Medical Laboratory Observer [Journal], Vol. 34 (6), pp 12-16,20. Available through MLO (http://www.mlo-online.com)
MEDCEU (1999). Breast Cancer and HER2. MEDCEU [On-line continuing education]. Available online at http://www.medceu.com/course-no-test.cfm?CID=307 through http://www.medceu.com.