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.
In addition to mutations in BRCA1 and BRCA2 (BRCA1/2) genes, mutations in the following genes can increase the risk of breast cancer:
Other genes are under study and may also play a role in breast cancer.
BRCA1/2 and other inherited gene mutations can be passed to you from either parent and can affect the risk of cancers in both women and men.
The risk from different types of inherited gene mutations can vary greatly. Some slightly increase breast cancer risk, while others (such as BRCA1/2 mutations) greatly increase risk. Inherited mutations known to increase the risk of breast cancer are rare in the general population.
In the U.S., 5-10 percent of breast cancers are related to an inherited gene mutation [3,24].
Like other gene mutations, BRCA1/2 mutations are rare in the general population. In the U.S., about 1 in 400 people have a BRCA1/2 mutation .
However, prevalence varies by ethnic group. Among Ashkenazi Jewish men and women, about 1 in 40 have a BRCA1/2 mutation .
The table below shows how the prevalence of BRCA1/2 mutations in women diagnosed with breast cancer varies by ethnic group (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
White (non-Ashkenazi Jewish)
Adapted from National Cancer Institute materials and Malone et al. [24,148].
Women who have a BRCA1/2 gene mutation (BRCA1/2 carriers) have an increased risk of breast cancer [25-27].
Estimates of risk are different for BRCA1 carriers and BRCA2 carriers [24,26-27]:
Women in the general population have about a 7 percent chance of getting breast cancer by age 70 . (Lifetime risk of breast cancer, up to age 95 and older, 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 these risks are not 100 percent. Many women with a BRCA1/2 mutation will never have breast cancer [25-27]. A combination of factors likely causes breast cancer.
BRCA1/2 mutations are thought to explain a large portion of hereditary breast cancers .
Most breast cancers, however, are not related to inherited gene mutations.
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) [24,149-150].
Triple negative breast cancers are:
BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [24,149-150].
Learn about hormone (estrogen and progesterone) receptor status, HER2 status and other factors that affect prognosis and treatment.
A BRCA1/2 mutation can increase the risk of a second primary breast cancer (a second breast tumor not related to the first one) [150-156].
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 [150-157].
The lifetime risk of a second primary contralateral breast cancer is about 40-70 percent for BRCA1/2 carriers [154,157].
For a summary of research studies on BRCA1 and BRCA2 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 (BRCA2 carriers) have an increased risk of breast cancer [24-25,27,158].
For example, the lifetime risk of breast cancer (up to age 80) is [159-162]:
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.
Learn about breast cancer screening for men with a BRCA1/2 gene mutation.
Men who have a BRCA1/2 mutation have an increased risk of prostate cancer [24,27,159,162,164].
The lifetime risk of prostate cancer (up to age 80) is [2,162]:
Learn about prostate cancer screening for men with a BRCA1/2 gene mutation.
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 :
BRCA1/2 carriers can reduce their risk of both breast and ovarian cancer by having prophylactic oophorectomy (surgical removal of the ovaries) [147,166].
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) [24,27].
However, data are limited and these topics are still under study.
Most risk factors for breast cancer likely impact breast cancer 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 [171-172].
However, certain reproductive and lifestyle factors may affect risk in BRCA1/2 carriers differently than in non-carriers.
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.
Very low doses of radiation (such as from X-rays) don't have much, if any, impact on breast cancer risk.
While the radiation exposure during screening mammography can increase the risk of breast cancer over time, this increase is very small [167-169].
For BRCA1 and BRCA2 carriers however, there's some concern the radiation exposure from mammography before age 30 may increase breast cancer risk more than for other women .
This issue is under active study.
Learn more about radiation and breast cancer risk.
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 with 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
In addition to BRCA1/2 gene mutations, other inherited gene mutations increase the risk of breast cancer. Some also increase the risk of other cancers.
These gene mutations are more rare than BRCA1/2 mutations and there’s still much to learn about them. Most of these mutations don’t increase the risk of breast cancer as much as BRCA1/2 mutations do. Some have only recently been shown to increase the risk of breast cancer and data on the mutations and their cancer risks are still limited.
A summary of information on these gene mutations is presented in the table below. Data on most of these gene mutations are limited and the risks shown here are estimates.
With genetic testing today, it’s common to be tested for BRCA1/2 mutations along with multiple other high-risk gene mutations. This is called panel testing or multi-gene testing. (Genetic testing for high-risk mutations is only recommended for some people.)
Because panel testing is still relatively new, the specific set of mutations assessed can vary from test to test. This can have an impact on how results are interpreted and how the information is used .
As with any genetic testing, panel testing should only be done in a medical setting after a detailed discussion of risks and benefits with a genetic counselor or a trained physician or nurse .
Learn more about panel (multi-gene) testing.
There are special breast cancer screening guidelines for women (and men) who have a BRCA1/2 gene mutation.
Guidelines for women with other high-risk gene mutations are less clear. As more is learned about these mutations, the better guidelines can be personalized.
Learn more about special breast cancer guidelines for women with an inherited mutation in an ATM, CDH1, CHEK2, NBN, NF1, PALB2, PTEN, STK11 or TP53 (p53) gene.
There are special breast cancer and risk reduction guidelines for women who have a BRCA1/2 gene mutation.
Learn more about risk reduction options for women at higher risk of breast cancer.
Your family history of breast cancer and other health conditions is important to discuss with your health care provider. This information helps your provider understand your risk of breast cancer.
My Family Health History tool
BreastCancerTrials.org in collaboration with Susan G. Komen® offers a custom matching service to help you find a clinical trial for 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.
*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date at this time.
Facts for Life: Genetics and Breast Cancer
Questions to Ask Your Doctor: Genes and Inherited Breast Cancer
Facts for Life: Breast Cancer in Men
Research Fast Facts
BRCA Genes and Breast Cancer
Hereditary Breast Cancer
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