Breast cancer cells may have receptors (proteins) that hormones or a protein called HER2 can attach to and encourage the cells to grow. A pathologist tests the cancer cells that were taken during the biopsy or surgery for these receptors.
The results help you and your doctor decide on the most effective treatment for you.
Hormones help control how cells grow and what they do in the body. All men have small amounts of the hormones oestrogen and progesterone in their bodies. Hormones, particularly oestrogen, can encourage breast cancer cells to grow.
Most oestrogen in men is made from male sex hormones (androgens). The testicles make a small amount.
Breast cancer that has oestrogen receptors is called oestrogen receptor-positive or ER-positive breast cancer. The term ER is used because the American spelling of oestrogen is estrogen. Some hospitals also check if cells are progesterone receptor positive (PR-positive).
Most breast cancers in men are ER positive and they respond well to hormonal treatments.
Some breast cancers have too much of a protein (receptor) called HER2 (human epidermal growth factor receptor 2) on the surface of their cells. This is called HER2-positive breast cancer. The extra HER2 protein encourages the cancer cells to divide and grow.
It is usually treated with a targeted therapy drug, for example, trastuzumab (Herceptin®). HER2 positive breast cancer is uncommon in men.
Below is a sample of the sources used in our breast cancer in men information. If you would like more information about the sources we use, please contact us at email@example.com
European Society for Medical Oncology. Primary breast cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of oncology 26 (supplement 5): v8–v30. 2015.
Gradishar WJ, et al. Breast cancer in men. UpToDate online. June 2018.
Morrow M, et al. Chapter 79: malignant tumors of the breast. DeVita, Hellman and Rosenberg’s cancer: principals and practice of oncology (10th edition). Lippincott Williams and Wilkins. 2014.
National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management. July 2018.
National Institute for Health and Care Excellence (NICE). Advanced breast cancer: diagnosis and treatment. Clinical Guideline 81. February 2009, updated August 2017.
Scottish Intercollegiate Guidelines Network. SIGN 134. Treatment of primary breast cancer: a national clinical guideline. September 2013.
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editors, Dr Rebecca Roylance, Consultant Medical Oncologist; and Dr Mark Verrill, Consultant Medical Oncologist.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.
This content is currently being reviewed. New information will be coming soon.
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