BRCA1 and BRCA2 are human genes that produce proteins that help repair damaged DNA. When either of these genes is mutated or altered, DNA damage may not be repaired properly. As a result, cells are more likely to develop additional genetic alterations that can lead to cancer. A woman’s risk of developing breast and/or ovarian cancer is greatly increased if she inherits a deleterious (harmful) mutation in the BRCA1 gene or the BRCA2 gene.
Men with these mutations also have an increased risk of breast cancer, and both men and women who have harmful BRCA1 or BRCA2 mutations may be at increased risk of additional types of cancer.
About 12 percent of women in the general population will develop breast cancer sometime during their lives (1). By contrast, according to the most recent estimates, 55 to 65 percent of women who inherit a harmful BRCA1 mutation and around 45 percent of women who inherit a harmful BRCA2 mutation will develop breast cancer by age 70 years (2, 3). Men and women who inherit harmful BRCA1 or BRCA2 mutations, whether or not they develop cancer themselves, may pass the mutations on to their sons and daughters. If a person learns that he or she has inherited a harmful BRCA1 or BRCA2 mutation, this will mean that each of his or her siblings has a 50% chance of having inherited the mutation as well.
Because harmful BRCA1 and BRCA2 gene mutations are relatively rare in the general population, most experts agree that mutation testing of individuals who do not have cancer should be performed only when the person’s family history suggests the possible presence of a harmful mutation in BRCA1 or BRCA2.
Several screening tools are now available that doctors can use to help them with this evaluation (4). These tools assess family history factors that are associated with an increased likelihood of having a harmful mutation in BRCA1 or BRCA2, including:
A personal history of breast cancer at age 50 or younger
A personal history of triple negative breast cancer (breast cancer that is estrogen receptor-negative, progesterone receptor-negative and HER2/neu receptor-negative)
A personal or family history of male breast cancer
A personal or family history of bilateral breast cancer (cancer in both breasts)
A personal history of ovarian cancer
A parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin diagnosed with breast cancer at age 45 or younger
A mother, sister, daughter, grandmother, granddaughter, aunt, niece or first cousin diagnosed with ovarian cancer
A family history of both breast and ovarian cancers on the same side of the family (either mother’s or father’s side of the family)
Ashkenazi Jewish heritage and a family history of breast or ovarian cancer
There is only a very small chance that your family carries a BRCA1/2 mutation if:
You or an immediate family member is the only person in your family with breast cancer
The breast cancers in your family all occurred at older ages
In most cases, genetic testing is not recommended when there is a low chance of finding a mutation. Remember that most breast cancers are not due to a BRCA1/2 mutation.
Genetic tests can check for BRCA1 and BRCA2 mutations in people with a family history of cancer that suggests the possible presence of a harmful mutation in one of these genes. The test can be performed on a blood or saliva sample. It takes about three weeks to get results. If a harmful BRCA1 or BRCA2 mutation is found, several options are available to help a person manage their cancer risk.
Digital Mammography Specialists recommends patients speak to their doctor or other health care provider to address any health concern and before making any health care decision. Our breast imaging radiologists are always available to answer any questions about BRACA genes and breast cancer.
About the author: Raja P. Reddy, MD is a board certified diagnostic radiologist specializing in breast imaging. He is also a contributing editor for Digital Mammography Specialists, a leading provider of outpatient women’s imaging services in the greater Atlanta, GA area.
1. Antoniou A, Pharoah PD, Narod S, et al. Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case series unselected for family history: A combined analysis of 22 studies. American Journal of Human Genetics 2003; 72(5):1117–1130.
2. Chen S, Parmigiani G. Meta-analysis of BRCA1 and BRCA2 penetrance. Journal of Clinical Oncology 2007; 25(11):1329–1333.
3. Howlader N, Noone AM, Krapcho M, et al. (eds.). (2013) SEER Cancer Statistics Review, 1975-2010. Bethesda, MD: National Cancer Institute. Retrieved June 24, 2013.
4. U.S. Preventive Services Task Force. Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer in Women: Clinical Summary of USPSTF Recommendation. AHRQ Publication No. 12-05164-EF-3. December 2013.
DISCLAIMER: The information contained herein is not intended to be a substitute for professional medical advice, diagnosis or treatment in any manner. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding any medical condition.