Every cell in your body contains genes. Genes contain the blueprints (genetic code) for your body.
For example, genes contain the information that determines the color of your eyes. They also contain information that affects how the cells in your body grow, divide and die.
The information in your genes is passed on (inherited) from both your mother and your father. And, you can pass this information on to your children (both your daughters and sons).
Some changes in the genetic code that affect the function of the gene are called mutations. Mutations are rare.
Just as with other information in genes, mutations can be passed on from a parent to a child.
Many inherited gene mutations have little or no effect on health (good or bad). Others, however, can increase the risk of certain diseases, including breast cancer.
Only about 5-10 percent of all breast cancers diagnosed in the U.S. are due to inherited gene mutations known to increase risk [4,28].
Learn more about inherited gene mutations.
BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the best-known genes linked to breast cancer risk. Everyone has these genes, but some people have an inherited mutation in one or both that increases the risk of breast cancer.
BRCA1/2 mutations can be passed to you from either parent and can affect the risk of cancers in both women and men.
A person who has a BRCA1/2 mutation is sometimes called a BRCA1/2 carrier.
Like other gene mutations, BRCA1/2 mutations are rare in the general population. In the U.S., between 1 in 400 and 1 in 800 people have a BRCA1/2 mutation .
However, prevalence varies by ethnic group. Among Ashkenazi Jewish women and men, about 1 in 40 carry a BRCA1/2 mutation .
The table below shows how the prevalence of BRCA1/2 mutations varies among breast cancer survivors from different ethnic groups (in alphabetical order).
Prevalence of BRCA1 and BRCA2 mutations among U.S. women with breast cancer by ethnic group (in alphabetical order)
Less than 1%
Data not available
Caucasian (non-Ashkenazi Jewish)
Adapted from National Cancer Institute materials and Malone et al. [28,142].
If you or a family member has a BRCA1/2 gene mutation, you may have questions about what this may mean for you.
This section provides information on BRCA1/2 mutations and how they impact cancer risk, breast cancer screening recommendations and options for lowering breast cancer risk.
It also has information on genetic testing and other topics.
Learn more about:
Women who have a BRCA1/2 gene mutation have an increased risk of breast cancer [29-31].
Estimates of risk are different for BRCA1 carriers and BRCA2 carriers [28,30-31]:
Women in the general population have about an 8 percent chance of getting breast cancer by age 70 . (Lifetime risk of breast cancer, up to age 85, is about 12 percent .)
This means by age 70:
These numbers represent average risk, so the risk of breast cancer for any one woman with a BRCA1/2 mutation may fall outside this range.
Note that these risks are not 100 percent. Many women with a BRCA1/2 mutation will never have breast cancer [29-31].
Together, BRCA1/2 mutations are thought to explain a large portion of hereditary breast cancers .
Most breast cancers, however, are not hereditary. A combination of factors likely causes breast cancer.
Learn about risk-reducing options for women at higher risk.
Learn about genetic testing.
Women who have a BRCA1 mutation have an increased risk of triple negative breast cancer (they tend to get breast cancers that are triple negative) [28,143-144].
Triple negative breast cancers are:
BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [28,143-144].
Learn about hormone (estrogen and progesterone) receptor status, HER2 status and other factors that affect prognosis and treatment.
Learn more about triple negative breast cancer.
Learn about molecular subtypes of breast cancer.
A BRCA1/2 mutation can increase the risk of a second primary breast cancer (a second breast tumor not related to the first one) [145-150].
These tumors usually occur in the contralateral (opposite) breast rather than in the same breast as the first cancer.
For BRCA1/2 carriers, the chance of a contralateral breast cancer 10 years after diagnosis of the first cancer is about 10-30 percent compared to about 5-10 percent for breast cancer survivors without a BRCA1/2 mutation [145-150].
The lifetime risk of a second primary contralateral breast cancer is about 40-65 percent for BRCA1/2 carriers .
BRCA1/2 carriers diagnosed with breast cancer in one breast may consider contralateral prophylactic mastectomy to reduce the risk of a second primary breast cancer in the opposite breast . This should be discussed with a health care provider.
For a summary of research studies on BRCA1/2 mutations and breast cancer, visit the Breast Cancer Research Studies section.
Men can also have BRCA1/2 mutations and may pass them on to their children.
Men who have a BRCA2 mutation have an increased risk of breast cancer [28-29,31,151].
In men, the lifetime risk of breast cancer is 1 in 1,000 for non-carriers and about 65 in 1,000 for BRCA2 carriers [149,152].
While 5-10 percent of breast cancers in women are thought to be due to gene mutations, up to 40 percent of breast cancers in men may be related to BRCA2 mutations .
This means men who get breast cancer are more likely to have an inherited gene mutation than women who get breast cancer.
Men who have a BRCA1 mutation may also have an increased risk of breast cancer, but this link is less clear .
Learn more about breast cancer in men.
Men who have a BRCA2 mutation may also have an increased risk of prostate cancer [28,152,154].
For BRCA2 carriers, the lifetime risk of prostate cancer (up to age 65) is about 15 percent .
Learn about genetic testing.
BRCA1/2 mutations increase a woman's risk of ovarian cancer .
The lifetime risk of ovarian cancer (up to age 70) is :
Although BRCA1/2 carriers have a higher risk of ovarian cancer than non-carriers, this does not mean carriers have a worse prognosis if they are diagnosed.
In fact, BRCA1/2 carriers who get ovarian cancer appear to have better survival than non-carriers .
Compared to non-carriers with ovarian cancer :
One reason for improved survival may be that BRCA1/2-related ovarian cancers appear to have a better chemotherapy response than other ovarian cancers [250-251].
Long-term data on survival in BRCA1/2 carriers diagnosed with ovarian cancer are limited.
One study found that 10 years after diagnosis, overall survival for BRCA1/2 carriers was about the same as for non-carriers .
BRCA1/2 carriers can reduce their risk of both ovarian and breast cancer by having prophylactic oophorectomy (surgical removal of the ovaries) [141,156].
Learn more about prophylactic oophorectomy.
BRCA1/2 carriers may also have an increased risk of pancreatic cancer and some second primary cancers (new cancers that develop after a first breast cancer) .
However, data are limited and these topics are still under study.
For a summary of research studies on BRCA1/2 mutations and cancer, visit the Breast Cancer Research Studies section.
Genetic testing gives people the chance to learn if their family history of breast cancer is due to an inherited gene mutation.
Most women who get breast cancer do not have a BRCA1/2 gene mutation.
Genetic testing is recommended only for certain people, including those with :
In most cases, testing is first done on the person with breast ovarian, pancreatic or aggressive prostate cancer.
If no mutation is found, the cancer was probably not due to a BRCA1 or BRCA2 gene mutation and other family members do not need to be tested.
If a mutation is found, other family members can be tested for the specific BRCA1 or BRCA2 mutation found in the person with cancer.
It’s not likely that all family members will have the mutation.
For example, if your mother has a BRCA1 or BRCA2 mutation, there is a 50 percent chance you will also have a mutation (you get half of your genes from your mother and half from your father).
Although testing for a BRCA1/2 mutation just requires a blood sample, the risks and benefits should be considered before testing.
A health care provider or genetic counselor can help you decide whether genetic testing is appropriate for you and your family.
Testing costs are usually covered by health insurance for people who fall into one of the categories above (for whom genetic testing is recommended).
Meet Terri Swain, a BRCA2 carrier and breast cancer survivor who had genetic testing.
Learn more about genetic testing.
Learn More | Current Article
Breast cancer screening tests are used to find cancer in a person who has no warning signs or symptoms.
For BRCA1/2 carriers, breast cancer screening tests include:
For a summary of research studies on breast MRI plus mammography versus mammography alone for women at higher risk of breast cancer, visit the Breast Cancer Research Studies section.
BRCA1/2 carriers should be aware of the warning signs of breast cancer (for women and for men).
BRCA1/2 carriers need to be screened for breast cancer at an earlier age and more frequently than other women.
The National Comprehensive Cancer Network (NCCN) recommends :
Clinical breast exam
Every 6-12 months
Not recommended unless breast MRI is not available or if there is a family history of breast cancer before age 30 (in these cases, every year)
Although not recommended for all men, breast cancer screening is recommended for :
For men who fall into one of the groups above, the NCCN recommends :
Most risk factors for breast cancer in women likely impact risk in BRCA1/2 carriers just as in non-carriers.
For example, exercise and breastfeeding appear to decrease the risk of breast cancer in both BRCA1/2 carriers and non-carriers [161-162].
However, certain reproductive and lifestyle factors may affect risk differently for BRCA1/2 carriers than non-carriers.
Very low doses of radiation (such as from X-rays) do not have much, if any, impact on breast cancer risk.
While the radiation during mammography can increase the risk of breast cancer over time, this increase is very small [157-159].
For BRCA1/2 carriers however, there is some concern that the radiation exposure from screening mammography before age 30 may increase breast cancer risk more than for other women .
This issue is under active study.
Learn more about exercise and breast cancer risk.
Learn more about breastfeeding and breast cancer risk.
Learn more about having children, age at first childbirth and breast cancer risk.
Learn more about alcohol and breast cancer risk.
Learn more about birth control pill use and breast cancer risk.
Learn more about radiation and breast cancer risk.
Many risk factors for breast cancer in men are different from those in women.
Whether the risk factors for breast cancer in men with a BRCA1/2 mutation are the same as those for men without a mutation has not been well studied.
Learn about risk factors for breast cancer in men.
Women who are BRCA1/2 carriers have medical options to help lower their risk of breast cancer.
If you are a BRCA1/2 carrier, talk with your health care provider about the pros and cons of these options.
Take the time to make decisions that are right for you. Don’t feel you need to rush.
For women at high risk of breast cancer, tamoxifen and raloxifene can lower the risk of :
Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive breast cancers. Neither drug reduces the risk of estrogen receptor-negative cancers .
Both pre- and postmenopausal women can take tamoxifen. Only postmenopausal women can take raloxifene.
Tamoxifen is more effective than raloxifene in lowering breast cancer risk, but raloxifene has fewer harmful side effects . This makes raloxifene a better choice for some women.
Learn more about the side effects of tamoxifen and raloxifene.
For a summary of research studies on the use of tamoxifen and raloxifene to reduce the risk of breast cancer, visit the Breast Cancer Research Studies section.
Learn more about risk-lowering drugs.
Bilateral prophylactic (PRO-fih-LAK-tik) mastectomy is the removal of both breasts to prevent breast cancer.
Bilateral prophylactic mastectomy may:
Some women choose this option because it eases their worries about getting breast cancer. It may also make them feel they have done all they can do to lower their risk of breast cancer.
If you are a BRCA1/2 carrier, talk with your doctor about the risks and benefits of all your risk-lowering options to make decisions that are right for you.
Learn more about prophylactic mastectomy.
Prophylactic oophorectomy is the surgical removal of the ovaries.
It may [166,257,259-264]:
NCCN recommends that women from families with hereditary ovarian cancer syndromes, including BRCA1/2 carriers, have oophorectomy between ages 35-40 (or after childbearing is complete) .
BRCA2 carriers tend to be diagnosed with ovarian cancer at a later age than BRCA1 carriers . So, BRCA2 carriers who have had bilateral prophylactic mastectomy may delay oophorectomy until age 40-45 .
Some support groups are tailored to BRCA1/2 carriers and people with BRCA1/2-related breast cancers.
Our Support section offers a list of resources to help find a local or online support group. For example, FORCE is an organization that has online support for women affected by hereditary breast and/or ovarian cancer.
Sharsheret has online support for Jewish women affected by hereditary breast and/or ovarian cancer.
SUSAN G. KOMEN® SUPPORT RESOURCES
BreastCancerTrials.org in collaboration with Susan G. Komen offers a custom matching service to help you find a clinical trial recruiting people with a BRCA1/2 or other gene mutation.
You can also visit the National Institutes of Health's website to find a clinical trial.
Learn more about clinical trials.
2016 Research Fast Facts
BRCA Genes and Breast Cancer
Hereditary Breast Cancer
Genetics and Breast Cancer
Questions to Ask Your Doctor: Inherited Genes and Breast Cancer Risk