BRCA1 and BRCA2
BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the most well-known genes linked to breast cancer.
This section provides information on BRCA1/2 inherited gene 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 about BRCA1/2 inherited gene mutations in women.
Learn about BRCA1/2 inherited gene mutations in men.
Genes and inherited gene mutations
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 your mother and your father. And, you can pass this information on to your children (your daughters and your sons).
Inherited gene mutations
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.
You get half of your genes from your mother and half from your father. So, for example, if your mother has a BRCA1 gene mutation, there’s a 50 percent chance you will also have a BRCA1 mutation.
Inherited gene mutations are also called germline mutations.
Inherited gene mutations and health
Many inherited gene mutations have little or no effect on health (good or bad). Others can increase the risk of certain diseases, including breast cancer.
In the U.S., 5-10 percent of breast cancers are related to an inherited gene mutation [4,28].
Learn more about inherited gene mutations.
BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations
Everyone has BRCA1 and BRCA2 genes. Some people have an inherited mutation in one or both of these genes that increases the risk of breast cancer.
BRCA1/2 inherited gene mutations can be passed to you from either parent. They 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.
Prevalence of BRCA1/2 inherited gene mutations in the U.S.
Like other inherited 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 .
Prevalence varies by ethnic group. Among Ashkenazi Jewish women and men, about 1 in 40 have a BRCA1/2 mutation .
Prevalence of BRCA1/2 inherited gene mutations among U.S. women with breast cancer
The table below shows the prevalence of BRCA1/2 inherited gene mutations in women diagnosed with breast cancer by ethnic group (in alphabetical order).
Prevalence of BRCA1/2 inherited gene mutations among U.S. women with breast cancer by ethnic group (in alphabetical order)
Data not available
Less than 1%
Data not available
White (non-Ashkenazi Jewish)
Data not available
Adapted from National Cancer Institute materials and Malone et al. [28,196].
BRCA1 and BRCA2 inherited gene mutations in women
If you or a family member has a BRCA1/2 inherited gene mutation, you may have questions about what this means for you. Learn more about:
- Breast cancer risk
- Ovarian cancer risk
- Risk of other cancers
- Genetic testing
- Breast cancer screening recommendations
- BRCA1/2 mutations and risk factors for breast cancer
- Risk-lowering options
- Clinical trials
Breast cancer risk in women with a BRCA1/2 inherited gene mutation
Women who have a BRCA1 or BRCA2 inherited gene mutation have an increased risk of breast cancer [28-32].
Estimates of risk are different for BRCA1 carriers and BRCA2 carriers. By age 70, the chance of developing breast cancer is [3,28,30-34,155,189]:
- 55-65 percent for women who have a BRCA1 gene mutation
- 45-55 percent for women who have a BRCA2 gene mutation
- 7 percent for women in the general population (Lifetime risk of breast cancer is 12 percent.)
This means by age 70:
- In a group of 100 women with a BRCA1/2 gene mutation, 45-65 will get breast cancer
In a group of 100 women without a BRCA1/2 gene mutation, about 7 will get breast cancer
These numbers represent average risk, so the risk of breast cancer for any one woman with a BRCA1/2 gene mutation may fall outside this range.
Note these risks are not 100 percent. Many women with a BRCA1/2 gene mutation will never have breast cancer [28-32]. A combination of factors likely causes breast cancer.
BRCA1/2 gene 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-lowering options for women at higher risk.
Learn about genetic testing.
Triple negative breast cancer
Triple negative breast cancers are:
- Estrogen receptor-negative (ER-negative)
- Progesterone receptor-negative (PR-negative)
BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [28,204-205].
Second primary 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) [28,206-211].
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 women without a BRCA1/2 gene mutation [32,206-211].
The lifetime risk of a second primary contralateral breast cancer is about 40-80 percent for BRCA1/2 carriers [32,189,208,211].
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 [155,188]. This should be discussed with a health care provider.
For a summary of research studies on BRCA1/2 inherited gene mutations and breast cancer, visit the Breast Cancer Research Studies section.
Lowering the risk of breast cancer
Ovarian cancer risk in women with a BRCA1/2 inherited gene mutation
BRCA1/2 inherited gene mutations increase a woman’s risk of ovarian cancer .
The lifetime risk of ovarian cancer (up to age 70) is :
- 35-70 percent for women who have a BRCA1 gene mutation
- 10-30 percent for women who have a BRCA2 gene mutation
- Less than 2 percent for women in the general population
Ovarian cancer survival
Although BRCA1/2 carriers have a higher risk of ovarian cancer than non-carriers, this doesn’t mean carriers have a worse prognosis if they are diagnosed.
BRCA1/2 carriers who get ovarian cancer appear to have better survival than non-carriers in the first 5 years after diagnosis [213-214]. One reason for this improved survival may be that BRCA1/2-related ovarian cancers appear to have a better response to chemotherapy than other ovarian cancers [215-216].
Long-term data on survival in BRCA1/2 carriers diagnosed with ovarian cancer are limited.
Lowering the risk of ovarian cancer
Prophylactic oophorectomy may also lower the risk of breast cancer .
For a summary of research studies on BRCA1/2 inheited gene mutations and ovarian cancer, visit the Breast Cancer Research Studies section.
Risk of other cancers in women with a BRCA1/2 inherited gene mutation
BRCA1/2 inherited gene mutations increase the risk of pancreatic cancer [28,155].
The National Comprehensive Cancer Network (NCCN) does not recommend pancreatic cancer screening for all women with a BRCA1/2 gene mutation . However, the NCCN recommends some women who also have a close family member with pancreatic cancer consider pancreatic cancer screening .
Women who have a BRCA2 gene mutation have an increased risk of melanoma [28,155].
Although the NCCN does not have melanoma screening guidelines for women with a BRCA2 mutation, it does recommend they consider yearly full-body skin exams to check for signs of melanoma and limit sun exposure .
BRCA1/2 gene mutations may also increase the risk of other cancers . However, data are limited and these topics are still under study.
For a summary of research studies on BRCA1/2 inherited gene mutations and cancer, visit the Breast Cancer Research Studies section.
Prognosis for BRCA1/2-related breast cancer
With treatment, women who have a BRCA1/2 inherited gene mutation appear to have similar breast cancer survival as women who don’t have a BRCA1/2 gene mutation [217-218].
Treatment for BRCA1/2-related breast cancer
In general, breast cancers related to a BRCA1/2 inherited gene mutation are treated in the same way breast cancers not related to a BRCA1/2 gene mutation are treated.
However, some drug therapies may be more effective in treating BRCA1/2-related breast cancers than other breast cancer .
The PARP inhibitors olaparib (Lynparza) and talazoparib (Talzenna) are used to treat metastatic breast cancers in some people who have BRCA1/2 gene mutations. These drugs are not used to treat breast cancers in people who don’t have BRCA1/2 gene mutations.
Platinum-based chemotherapy drugs (such as carboplatin) may be better at treating BRCA1/2-related breast cancers than other breast cancers [220-222]. This is under study.
Learn more about emerging areas in drug therapies for early breast cancer.
Learn more about emerging areas in drug therapies for metastatic breast cancer.
Genetic testing gives people the chance to learn if their breast cancer or family history of breast cancer is due to an inherited gene mutation.
Most women who get breast cancer don’t have a BRCA1 or BRCA2 inherited gene mutation.
Who should consider genetic testing?
Genetic testing is only recommended for people with a high risk of having a BRCA1/2 inherited gene mutation (or other high-risk inherited gene mutation related to breast cancer), including those with :
- A family member with a BRCA1/2 inherited gene mutation (or other inherited gene mutation related to breast cancer)
- A personal history of breast cancer at age 45 or younger
- A personal history of triple negative breast cancer (breast cancer that is estrogen receptor-negative, progesterone receptor-negative and HER2-negative) diagnosed at age 60 or younger
- Ashkenazi Jewish heritage and a personal history of breast cancer
- A personal history of breast cancer at age 46-50 and a close family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin) diagnosed with breast cancer at any age
- A personal history of breast cancer at any age and a close family member diagnosed with breast cancer at age 50 or younger
- A personal history of breast cancer at any age and 2 or more close family members diagnosed with breast cancer at any age
- A family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew or niece) diagnosed with breast cancer at age 45 or younger
- A personal or family history of ovarian cancer, pancreatic cancer, aggressive prostate cancer or metastatic prostate cancer
- A personal or family history of male breast cancer
In most cases, testing for BRCA1/2 inherited gene mutations is first done on the person with breast, ovarian, pancreatic or prostate cancer.
- If no mutation is found, the cancer was not due to a BRCA1/2 gene mutation.
- If a BRCA1/2 gene mutation is found, other family members can be tested for the specific mutation.
Just because one person in a family has an inherited gene mutation doesn’t mean everyone in the family has the mutation. Only identical twins have the exact same genes. Other family members share some, but not all, of their genes.
For example, if your mother has a BRCA1 gene mutation, there’s a 50 percent chance you will also have a BRCA1 gene mutation (you get half of your genes from your mother and half from your father).
Weighing the risks and benefits of genetic testing
A health care provider or genetic counselor can help you decide whether genetic testing is right for you and your family.
Testing for a BRCA1/2 gene mutation only requires a blood or saliva sample, but there are risks and benefits to consider before testing. There can be physical, emotional and financial impacts of knowing your genetic status.
Testing costs are usually covered by health insurance for people who fall into one of the categories above (for whom genetic testing is recommended).
Learn more about genetic testing.
Breast cancer screening
Breast cancer screening tests are used to find cancer in a person who has no warning signs or symptoms.
BRCA1 and BRCA2 carriers need to be screened for breast cancer starting at an earlier age and more frequently than other women. They should also be aware of the warning signs of breast cancer.
Every 6-12 months
Only if breast MRI is not available: Every year
Every year (if breast MRI is not available, mammogram)
Every 6-12 months
Learn more about breast cancer screening recommendations for women at higher risk.
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 inherited gene mutations and risk factors for breast cancer
Most risk factors for breast cancer in women likely impact risk the same way for BRCA1 and BRCA2 carriers and non-carriers.
However, breast cancer risk in BRCA1/2 carriers with certain reproductive and lifestyle factors may be different from risk in non-carriers.
- Having children and a younger age at first childbirth are linked to a lower risk of breast cancer in the general population. In BRCA1/2 carriers however, some studies show no link between these factors and breast cancer risk [223,226-229].
- Drinking alcohol and current or recent use of birth control pills are linked to an increased risk of breast cancer in the general population. It’s unclear whether these factors are linked to risk in BRCA1/2 carriers [223,226-227,230-231].
People exposed to very low doses of radiation (such as from X-rays) don’t have much, if any, impact on breast cancer risk.
However, there’s some concern the radiation exposure from screening mammograms at younger ages is linked to a higher risk of breast cancer in BRCA1/2 carriers than in other women . This issue is under study.
Breast MRI does not use radiation. The NCCN recommends women ages 25-29 who have a BRCA1/2 gene mutation get breast cancer screening with a breast MRI every year . Mammography is not recommended for these young women unless breast MRI is not available .
Women who have a BRCA1 /2 inherited gene mutation 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.
Tamoxifen and raloxifene are FDA-approved for breast cancer risk reduction in women at high risk.
Both tamoxifen and raloxifene can lower the risk of :
- Invasive breast cancer
- Non-invasive breast cancer, such as ductal carcinoma in situ (DCIS)
Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive breast cancers. Neither drug reduces the risk of estrogen receptor-negative cancers .
Both premenopausal women 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. Both drugs can cause menopausal symptoms such as hot flashes.
Learn more about the side effects of tamoxifen and raloxifene.
Learn about treating menopausal symptoms.
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.
Aromatase inhibitors are hormone therapy drugs used to treat estrogen receptor-positive breast cancer.
Findings from randomized controlled trials have shown the aromatase inhibitors exemestane and anastrozole may lower the risk of developing breast cancer in postmenopausal women at higher risk [266-267].
The American Society for Clinical Oncology (ASCO), the National Comprehensive Cancer Network (NCCN) and the U.S. Preventive Services Task Force list exemestane and anastrozole as risk-lowering drug options for postmenopausal women at higher risk of breast cancer.
However, these drugs do not have FDA-approval for use in the risk reduction setting. They are only FDA-approved for use in breast cancer treatment.
Learn about aromatase inhibitors and breast cancer treatment.
Learn more about risk-lowering drugs.
Preventive surgery — prophylactic mastectomy and prophylactic oophorectomy
Bilateral prophylactic mastectomy is the removal of both breasts to prevent breast cancer.
Bilateral prophylactic mastectomy may:
- Lower the risk of breast cancer by 90 percent or more in women who are BRCA1/2 carriers [155,236-239]
- Add 3-5 years to the lifespan of a 30-year old woman who is a BRCA1/2 carrier [240-241]
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 health care provider about the pros and cons of each risk-lowering option and make the decision that’s right for you.
Learn more about prophylactic mastectomy.
Learn about breast reconstruction after mastectomy.
Prophylactic oophorectomy is the surgical removal of the ovaries to prevent ovarian cancer. It can lower the risk of ovarian cancer by 70 to over 90 percent [155,240,242-248].
The NCCN recommends women with BRCA1/2 mutations, have an oophorectomy between ages 35-40 (or after childbearing is complete) to lower their risk of ovarian cancer .
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 .
Prophylactic oophorectomy may also lower the risk of breast cancer .
For premenopausal women, prophylactic oophorectomy leads to early menopause.
Learn more about early menopause and how to manage its symptoms.
Some support groups are tailored to BRCA1 and BRCA2 carriers and people with BRCA1/2-related breast cancers.
For example, FORCE is an organization that offers online support for people at higher than average risk of breast, ovarian or other cancers due to family history or inherited gene mutations.
Sharsheret offers online support for Jewish women affected by hereditary breast and/or ovarian cancer.
SUSAN G. KOMEN® SUPPORT RESOURCES
The NCCN encourages BRCA1/2 carriers to consider participating in cancer screening or imaging clinical trials.
Susan G. Komen® Breast Cancer Clinical Trial Information Helpline
If you or a loved one needs information or resources about clinical trials, call our Clinical Trial Information Helpline at 1-877 GO KOMEN (1-877- 465- 6636) or email email@example.com.
BreastCancerTrials.org in collaboration with Susan G. Komen® offers a custom matching service to help find clinical trials on risk reduction. BreastCancerTrials.org can also help find breast cancer treatment clinical trials for people who have a BRCA1/2 inherited gene mutation.
You can also visit the National Institutes of Health’s website to find clinical trials.
Learn more about clinical trials.
Insurance issues and financial assistance
If you have insurance issues (such as a claim is denied) or need help paying for genetic testing, risk-lowering drugs or other out-of-pocket expenses, there are resources that may help.
Susan G. Komen® created the Komen Treatment Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals.
Funding is available for eligible individuals of any age undergoing breast cancer treatment, at any stage of the disease. To learn more about this program and other helpful resources, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636).
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