BRCA1 & BRCA2
How common are BRCA1 and BRCA2 mutations?
- In the general population, between one in 300 and one in 800 individuals carry a BRCA1 or 2 or mutation.1
- For individuals of Ashkenazi Jewish ancestry, one in 40 individuals carry a BRCA1 or 2 mutation.
What percentage of breast and ovarian cancers are caused by BRCA1 or BRCA2 mutations?
- 5 percent-10 percent of all breast cancer.
- Up to 15 percent of ovarian cancers.1-4
What are the lifetime cancer risks associated with BRCA1 and BRCA2 mutations?
- Breast cancer: 44 percent-87 percent
- Ovarian cancer: 20 percent-50 percent
- Male breast cancer and pancreatic cancer: ~7 percent
Which patients should I refer to a genetic counselor for risk assessment and discussion of genetic testing for BRCA1 and BRCA2 mutations?
Patients who have a personal or family history (this includes maternal or paternal lineages) or those who have had:1-2,4
- Breast cancer at a young age (younger than age 50)
- Ovarian cancer at any age
- Bilateral breast cancer or 2 or more primary tumors of the breast
- Breast and ovarian cancer
- Breast cancer and are male
- Two or more biological relatives* on the same side of the family with breast and/or ovarian cancer (*parent, child, siblings, grandparent, grandchild, aunt/uncle, niece/nephew, first cousin)
- Breast or ovarian cancer and are of Ashkenazi Jewish ancestry
- Confirmed BRCA1 or BRCA2 mutation in their family
Specific indications for genetic counseling and testing vary among professional organizations. The indications above are to be used as a guide and are not a substitute for clinical judgment. Not all clinical scenarios can be anticipated such as when there is a limited family structure or family medical history.
What are the benefits of genetic counseling when offering BRCA1 and BRCA2 testing?
- Patient education and informed consent are critical aspects of the genetic testing process and will help individuals decide if genetic testing is right for them.
- Pre-test counseling addresses the implications of potential test results, medical management options, psychosocial challenges, laws protecting against genetic discrimination, other options for testing and testing costs. Examples include:
- The possibility of false negative results because genes other than BRCA1 and 2 may be responsible for cancers in the family
- The possibility of test results with mutations noted to have “uncertain clinical significance”
- The cost of BRCA gene testing differs depending on which level of testing is indicated ($440-$3,770)
- The possibility of indirectly disclosing non-paternity, non-disclosed adoptions or use of egg or sperm donation
- If help is needed, a genetics health care professional also can provide assistance with dissemination of relevant information to at-risk family members.
Genetics health care professionals:
BRCA1 and BRCA2 referral, testing and risk management guidelines:
- American College of Obstetrics and Gynecology (ACOG)
– ACOG Practice Bulletin. Obstet Gynecol. 113(4):957-966. 4/2009
- American Society of Clinical Oncology (ASCO)
– JCO Vol 21(12):2397-2406. 6/2003.
- National Cancer Institute (NCI)
- National Comprehensive Cancer Network (NCCN)
- U.S. Preventative Services Task Force (USPSTF)
Patient friendly facts about genetic testing for breast and ovarian cancer risk
- U.S. Centers for Disease Control and Prevention
- Facing Our Risk of Cancer Empowered (FORCE
- National Cancer Institute
- National Institute of Health – Genetics Through a Primary Care Lens: A Web-Based Resource for Faculty Development
- Berliner, J.L. et al. (2007) Risk assessment and genetic counseling for hereditary breast and ovarian cancer: Recommendations of the National Society of Genetic Counselors. Journal of Genetic Counseling. 16:241-260.
- U.S. Centers for Disease Control and Prevention. Located September 4, 2009, at http://www.cdc.gov/genomics/training/perspectives/factshts/breastcancer.htm
- Pinsky, L.E., et al. (2001) Why should primary care physicians know about breast cancer genetics? Western Journal of Medicine. 175:168-173.
- Guidelines listed in Resources above.
- CDC: Breast & Ovarian Cancer
- Facing Our Risk of Cancer Empowered
- NSGC - Find a Genetic Counselor
- National Center for Biotechnology Information
- National Comprehensive Cancer Network
- NIH: Gene Tests
- National Society of Genetic Counselors
- U.S. Preventative Services Task Force: BRCA-Related Cancer
- IL Clinical Genetic Centers
- Fact Sheet: BRCA1-2
- Fact Sheet: Lynch Syndrome for Health Care Professionals
- Fact Sheet: Lynch Syndrome for Public
- Fact Sheet: Prenatal Diagnostic Tests
- Fact Sheet: Prenatal Diagnostic Tests (En Español)
- Fact Sheet: Prenatal Screening Tests
- Fact Sheet: Prenatal Screening Tests (En Español)
- Fact Sheet: Noninvasive Prenatal Testing - For Consumers
- Fact Sheet: Noninvasive Prenatal Testing - For Physicians
- Family Health History Record Keeper
- Genetics Program Manual for Local Health Departments (2008)
- IL State Genetics Plan (2007)