The biopsy sample will be sent for more testing to determine: estrogen receptor and progesterone receptor status, HER2 status, and triple negative status, and genomic assays.
- Estrogen receptor (ER) and progesterone receptor (PR) status: Estrogen and progesterone are hormones produced by the ovaries. If a tumor has ER or PR receptors, it may grow in response to these hormones. About 60 to 75 percent of breast cancers depend on estrogen or progesterone to grow. Treatment of these tumors may include hormone therapies such as tamoxifen. They block the action of estrogen or progesterone to keep the tumor from growing.
- HER2 status: 20 to 25 percent of breast cancers involve overproduction of a protein called human epidermal growth factor receptor 2 (HER2). These proteins help some tumors grow. Drugs like Herceptin® (trastuzumab) attach to the HER2 receptors on breast cancer cells, blocking them from receiving growth signals.
- Triple negative status: About 10 to 15 percent of tumors have "triple negative" status. This means that they do not have ER or PR receptors and do not make much HER2 protein. Triple-negative breast cancer can be difficult to treat mainly because it grows and spreads quickly. There are also fewer targeted medicines that treat triple-negative breast cancer.
- Genomic assays test the genes in the tumor. The activity of certain genes shows how likely the tumor is to grow and spread. They can help guide whether more treatments like chemotherapy will be needed after surgery. The number of genes that are tested varies.
Other factors will also impact your surgery and treatment decisions:
- Mutations in the BRCA1 and BRCA2 genes increase a woman's risk of developing breast and/or ovarian cancer. Women carrying a BRCA mutation have a lifetime risk (if they live to the age of 85) of 80 percent for developing breast or ovarian cancer.29
- Women in some ethnic groups have a higher chance of carrying a BRCA mutation. For example, 1 of 40 Ashkenazi Jewish women carry a BRCA mutation.
- Previous radiation to the same area
- Preexisting lung disease, connective tissue disorders (like scleroderma), or systemic lupus erythematosus
The United States Preventive Services Task Force (USPSTF) recommends that primary care providers screen women who have family members with breast, ovarian, tubal, or peritoneal cancer. Women with positive screening results should receive genetic counseling and, if indicated after counseling, BRCA testing.30