This section provides information on BRCA1, BRCA2 and other high-risk gene mutations, and how these gene mutations impact breast cancer risk.
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 [4,27].
Like other gene mutations, BRCA1 and BRCA2 mutations are rare in the general population. In the U.S., about 1 in 400 people have a BRCA1/2 mutation .
Prevalence varies by ethnic group. Among Ashkenazi Jewish men and women, about 1 in 40 have a BRCA1/2 mutation .
The table below shows the prevalence of BRCA1/2 mutations in women diagnosed with breast cancer by ethnic group (in alphabetical order).
Prevalence of BRCA1/2 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. [27,176].
Women who have a BRCA1 or BRCA2 gene mutation (BRCA1/2 carriers) have an increased risk of breast cancer [28-30].
Estimates of risk are different for BRCA1 carriers and BRCA2 carriers. By age 70, the chance of developing breast cancer is [27,29-30]:
Women in the general population have about a 7 percent chance of getting breast cancer by age 70 . (The lifetime risk of breast cancer 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 [28-30]. 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) [27,177-178].
Triple negative breast cancers are:
BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [27,177-178].
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) [179-184].
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 [179-185].
The lifetime risk of a second primary contralateral breast cancer is about 40-70 percent for BRCA1/2 carriers [182,185].
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 and BRCA2 mutations and may pass them on to their children.
Men who have a BRCA2 mutation (BRCA2 carriers) have an increased risk of breast cancer [27-28,30,37].
For example, the lifetime risk of breast cancer (up to age 80) is [32-35]:
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 [27,30,32,35,187].
The lifetime risk of prostate cancer is [35,188]:
Learn about prostate cancer screening for men with a BRCA1/2 gene mutation.
Learn about genetic testing.
BRCA1 and BRCA2 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 ovarian cancer by having prophylactic oophorectomy (surgical removal of the ovaries) .
Prophylactic oophorectomy may also lower the risk of breast cancer .
BRCA1 and BRCA2 gene mutations increase the risk of prostate cancer (in men) and pancreatic cancer . They also increase the risk of a second primary breast cancer in the opposite (contralateral) breast [27,185]. These are new breast cancers that develop after a first breast cancer.
BRCA1/2 mutations may also increase the risk of other cancers . However, data are limited and these topics are still under study.
Learn more about BRCA1/2 mutations in women and BRCA1/2 mutations in men.
Most risk factors for breast cancer likely impact breast cancer risk the same way in BRCA1/2 carriers and non-carriers.
For example, exercise and breastfeeding appear to decrease the risk of breast cancer in both BRCA1/2 carriers and non-carriers [190-191].
However, certain reproductive and lifestyle factors may affect risk in BRCA1/2 carriers differently than in non-carriers, such as:
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 [196-197].
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 study.
Some support groups are tailored to people with BRCA1 and BRCA2 mutations and those with BRCA1/2-related breast cancers.
Our Support section offers a list of resources to help find local and online support groups. 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 and BRCA2 gene mutations, other inherited gene mutations increase the risk of breast cancer. Some also increase the risk of other cancers.
These gene mutations are less common than BRCA1/2 mutations and there’s still much to learn about them. Some of these mutations are linked to a high risk of breast cancer (similar to BRCA1/2 mutations) and others are linked to a moderate risk. A mutation in any of these other genes generally leads to changes in breast cancer screening recommendations.
The table below provides a summary about these other gene mutations. The risk estimates may change over time as more is learned about these mutations.
With genetic testing today, it’s common to be tested for multiple high-risk and moderate-risk gene mutations, including BRCA1/2 mutations. This is called panel testing or multi-gene testing. (Genetic testing for breast cancer risk is only recommended for some people.)
Because panel testing is still relatively new, the specific set of genes assessed for mutations can vary from test to test. A genetic counselor or a trained physician or nurse can help determine the best test (and lab), given the pattern of cancer in your family.
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.
For women who have a BRCA1/2 gene mutation, there are special breast cancer screening guidelines.
For men who have a BRCA1/2 gene mutation, there are special cancer screening guidelines.
Guidelines for people 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 or TP53 (p53) gene.
There are special breast cancer and risk reduction guidelines for women 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 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.
Susan G. Komen®'s My Family Health History Tool
My Family Health History tool is a web-based tool that makes it easy for you to record and organize your family health history. It can help you gather information that's useful as you talk with your doctor or genetic counselor.
BreastCancerTrials.org in collaboration with Komen offers a custom matching service to help you find clinical trials for people with a BRCA1, BRCA2 or other gene mutation.
You can also visit the National Institutes of Health's website to find clinical trials.
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: Inherited Genes & Breast Cancer Risk
Research Fast Facts
BRCA Genes and Breast Cancer
Hereditary Breast Cancer
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