About one out of every five breast cancer cases have too many of the human epidermal growth factor receptor 2 (HER2). HER2 status guides how we treat your breast cancer. At Penn Medicine, our breast cancer care experts provide precise diagnosis and testing to get you the most effective treatment for your diagnosis.
What is HER2-positive breast cancer?
All breast cells have and are tested for an excess of human epidermal growth factor receptor 2, commonly referred to as HER2. HER2 proteins are receptors that control how the cells grow and divide. When breast tissue has extra HER2 receptors (overexpression), breast cells can multiply too quickly. The growth may become uncontrolled and lead to a tumor.
Breast cancer identified as HER2-positive tends to grow faster, spread (metastatic breast cancer) and come back (recur). While HER2-positive cancer may be aggressive, it also responds better to breast cancer treatment that targets HER2 proteins. There are no unusual symptoms or breast cancer risk factors associated with HER2-positive breast cancer, although some studies suggest that HER2-positive status is more common among younger women.
Symptoms of HER2-positive breast cancer
HER2-positive breast cancer does not present itself through any unique symptoms. Common signs of this breast cancer type align with the typical breast cancer symptoms and may be detected by a mammogram at routine breast cancer screening:
- Changes in breast shape
- Mass or suspicious finding on a mammogram
- Breast lump
- Breast or nipple pain
- Discharge from the nipple
- Nipple inversion
- Swelling of the breast
- Thickening of the nipple skin
- Creasing in the breast
HER2-positive breast cancer is defined by the presence of excess HER2 proteins, which require testing and cannot be identified through symptoms.
Diagnosis and testing for HER2 status
After imaging confirms irregular cells, our breast pathologists test all breast tumor tissue using a sample taken during a breast biopsy to diagnose breast cancer. There are several tests that examine HER2. The most common tests used include:
- Immunohistochemistry (IHC) test: This test measures the amount of HER2 proteins found on breast cancer cells. The score will either be 0 to 1+ (HER2 negative), 2+ (borderline), or 3+ (HER2-positive).
- Florescent in situ hybridization (FISH) test: If an IHC test is borderline, this test provides more information about HER2. It looks for extra copies of the HER2 gene (which produces the HER2 protein). The result will be either positive or negative.
Breast tissue is also tested for hormone receptors (estrogen and progesterone). If a tumor tests positive for hormone receptors in addition to HER2, breast cancer may respond to hormone therapy. Cancer that tests negative for hormone receptors and HER2 is called triple negative breast cancer.
A positive test for HER2 means breast cancer may grow quickly and possibly come back (recur). This risk is significantly lowered with appropriate treatment. At Penn Medicine, we treat HER2-positive breast cancer with medications that work to slow or stop tumor growth.
Our approach to HER2-positive treatment
We know what fuels the growth of HER2-positive breast cancer. Our specialized oncologists use precision medicine that targets HER2 receptors along with standard breast cancer treatment to design individualized care. Breast cancer treatment for a HER2-positive diagnosis may include a variety of options.
Getting care at Penn Medicine for HER2-positive breast cancer
Our breast cancer team provides comprehensive care for every stage and type of breast cancer. Our specialized providers offer patient-centered, advanced treatment for people with HER2-positive breast cancer. The benefits of cancer care at Penn Medicine include:
- Precise diagnosis: The accuracy of HER2 tests often depends on the pathologist. Our specialized breast cancer pathologist works only with breast tissue. We provide you with the most accurate interpretation of your HER2 test.
- Leaders in targeted therapy: We are nationally recognized for our role in the development of targeted therapies. Our research and clinical trials continue to advance promising treatments for HER2-positive breast cancer.
- Attention to breast cancer recurrence: Our 2-PREVENT Breast Cancer Translational Center of Excellence helps you prevent, identify, and manage breast cancer recurrence associated with HER2-positive breast cancer.
- Care where you live: All Penn Medicine breast cancer locations provide expert breast cancer diagnosis, testing, and treatment. Specialists across the network work together seamlessly to get you personalized care.
- BRCA-related cancer research: Having a BRCA gene mutation is linked to an increased risk for developing certain cancers, including breast cancer. Penn Medicine’s Basser Center for BRCA has helped accelerate progress for BRCA-related cancer research and targeted therapies.
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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