Some breast cancer cells have characteristics that make the cancer easier to treat. We test all newly diagnosed breast cancer cells to see if they have hormone receptors, which fuel cancer growth. About two out of every three breast cancers have at least one type of hormone receptor.
At Penn Medicine, our specialized breast cancer care team is with you every step of the way, using precise details from your diagnosis to personalize treatment for every patient.
What is hormone receptor-positive breast cancer?
Hormone receptors are proteins found on breast cells. They pick up the estrogen or progesterone signals that promote cell growth, including cancer cell growth if they contain the receptors for those hormones. Breast cancer cells that have receptors for either hormone are considered hormone receptor-positive (HR+), or just hormone-positive.
Breast tumors may be positive for estrogen receptors (ER+), progesterone receptors (PR+), or both (ER/PR+). About 80 percent of all HR+ breast cancers are ER+ or ER/PR+.
If a cancer cell is ER+, it means it can receive signals from estrogen instructing the cells to grow. If a cancer cell is PR+, these signals can come from the progesterone hormone. Knowing whether the tumor needs estrogen or progesterone to grow makes it easier to treat the cancer. Breast cancer cells can test positive for hormone receptors regardless of the type of breast cancer or breast cancer stage.
Testing for estrogen and progesterone receptors (PR) for HR+ breast cancer
At Penn Medicine, our breast pathologists diagnose breast cancer by testing tumor tissue using samples taken during a breast biopsy or surgery. The most common test used to classify hormone receptor status is an immunohistochemistry (IHC) test. This sensitive test will identify a tumor as HR+ if even one percent of the tested cells have a hormone receptor.
Breast tissue is also tested for human epidermal growth factor receptor 2 (HER2). Breast cancer that is HER2-positive may respond to targeted therapy. Cancer that tests negative for hormone receptors and HER2 is called triple negative breast cancer.
Treatment options for HR+ breast cancer
Treatment for hormone receptor-positive breast cancer primarily focuses on blocking the estrogen and progesterone hormones that fuel tumor growth. Along with local treatments like surgery or radiation, patients typically undergo long-term endocrine therapy using medications like tamoxifen or aromatase inhibitors to drastically lower the risk of recurrence. For advanced or higher-risk cases, this foundational approach is often combined with targeted therapies, such as CDK4/6 inhibitors, to more effectively stop cancer cells from dividing.
Our approach to hormone receptor-positive breast cancer
We know how to identify a tumor’s characteristics and use that information to personalize breast cancer treatment. These steps are key in effective breast cancer care. At Penn Medicine you can expect:
- Expert diagnosis: Our specialized breast cancer pathologists only work with breast cancer tissue. We accurately interpret your test results, so you quickly get the treatment you need.
- Leaders in targeted therapy: Our renowned oncologists know when targeted therapy is appropriate for HR+ breast cancer and how to use it effectively.
- Support for side effects: We offer breast cancer support and integrative oncology to ease any discomfort and pain associated with treatment.
- Care close to home: We provide breast cancer expertise at all our Penn Medicine breast cancer locations. Oncologists throughout our network collaborate seamlessly to get you advanced breast cancer care.
- Focus on research and prevention of inherited cancer: Through the Basser Center for BRCA, Penn Medicine has been a leader in the research, treatment, and prevention of cancers linked to the BRCA gene mutation.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.
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