What Is HER2-Positive Breast Cancer?

HER2 positive breast cancer
(From L-R) Ian Krop, MD, PhD, Jean Zhao, PhD, and Shom Goel, MD, PhD, study treatments and drug resistance in HER2-positive breast cancers.

HER2-positive breast cancer is a subtype of breast cancer that affects about 20 percent of breast cancer patients. Around fifty percent of HER2-positive cancers also have hormone receptors for estrogen and/or progresterone. HER2, which stands for human epidermal growth factor receptor 2, is a gene in the cancer cell that makes the HER2-receptor protein. It is thought that signaling through the HER2 receptor is vital for the normal growth and spread of breast cells. Cancers that are HER2-positive can have either too many copies of the HER2 gene, or too many copies of the HER2 receptor, which causes cancer cells to grow.

How is HER2-positive breast cancer diagnosed?

The HER2 status of the breast cancer cells is determined through a biopsy. Pathologists use a variety of different tests to determine how many HER2 gene or receptors are in a patient’s cancer cells.

How is HER2-positive breast cancer treated?

While it varies for every patient, most treatment plans for HER2-positive breast cancer include both chemotherapy as well as a targeted medication against HER2. The most commonly used medication for HER2-positive breast cancer is Herceptin (trastuzumab) which is a monoclonal antibody against the HER2 receptor. The combination of chemotherapy and Herceptin can block HER2 signaling pathway, stopping cancer cell growth and leading to destruction of cancer cells. If a HER2-positive cancer also has hormone receptors, medications targeting hormone receptors may also be used as part of treatment. Although HER2-positive breast cancer can be more aggressive, current therapies are very effective and investigators with the Susan F. Smith Center for Women’s Cancers are leading and participating in several clinical trials looking to improve treatment for this subtype.

Learn more about the latest treatments for HER2-positive breast cancer in the presentation below: