BRCA1 and BRCA2
BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the most well-known genes linked to breast cancer risk.
This section provides information on BRCA1/2 gene mutations and how they impact cancer risk, breast cancer screening recommendations and options for lowering breast cancer risk. It also has information on BRCA1/2 genetic testing and other topics.
Learn about BRCA1/2 gene mutations in women.
Learn about BRCA1/2 gene mutations in men.
Genes and 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 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.
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.
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) 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 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.
Prevalence of BRCA1/2 gene mutations in the U.S.
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 .
Prevalence of BRCA1/2 gene mutations among U.S. women with breast cancer
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)
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. [28,180].
BRCA1 and BRCA2 mutations in women
If you or a family member has a BRCA1/2 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 mutation
Women who have a BRCA1 or BRCA2 gene mutation have an increased risk of breast cancer [29-31].
Estimates of risk are different for BRCA1 carriers and BRCA2 carriers. By age 70, the chance of developing breast cancer is [28,30-31]:
- 55-65 percent for BRCA1 carriers
- 45-55 percent for BRCA2 carriers
This means by age 70:
- In a group of 100 women without a BRCA1/2 mutation, about 7 will get breast cancer
- In a group of 100 women with a BRCA1/2 mutation, 45-65 will get breast cancer
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 [29-31]. 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-lowering options for women at higher risk.
Learn about genetic testing.
Triple negative breast cancer
Triple negative breast cancers are:
Second primary breast cancer
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 mutation diagnosed with breast cancer [32,184-189].
The lifetime risk of a second primary contralateral breast cancer is about 40-80 percent for BRCA1/2 carriers [32,181,186,189].
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 [147,179]. 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.
Lowering the risk of breast cancer
Ovarian cancer risk in women with a BRCA1/2 mutation
BRCA1/2 mutations increase a woman’s risk of ovarian cancer .
The lifetime risk of ovarian cancer (up to age 70) is :
- Less than 2 percent for women in the general population
- 35-70 percent for women with a BRCA1 mutation
- 10-30 percent for women with a BRCA2 mutation
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 . 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 mutations and ovarian cancer, visit the Breast Cancer Research Studies section.
Risk of other cancers in women with a BRCA1/2 mutation
Women with a BRCA1/2 gene mutation have an increased risk of pancreatic cancer [28,147].
There are no pancreatic cancer screening guidelines for people with BRCA1/2 mutations.
Women with a BRCA2 gene mutation have an increased risk of melanoma [28,147].
Although the NCCN does not have melanoma screening guidelines for people with a BRCA2 mutation, it does recommend they consider yearly full-body skin exams to check for signs of melanoma and limiting sun exposure .
BRCA1/2 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 mutations and cancer, visit the Breast Cancer Research Studies section.
Prognosis for BRCA1/2-related breast cancer
With treatment, women with a BRCA1 or BRCA2 mutations appear to have similar breast cancer survival as women without BRCA1/2 mutations [217-218].
Treatment for BRCA1/2-related breast cancer
In general, breast cancers related to BRCA1 and BRCA2 mutations are treated in the same way breast cancers not related to BRCA1/2 mutations 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 gene mutation.
Who should consider BRCA1/2 genetic testing?
BRCA1/2 is only recommended for people with a high risk of having a BRCA1/2 gene mutation, including those with :
- A family member with a BRCA1/2 gene mutation (or other inherited gene mutation linked to breast cancer)
- A personal history of breast cancer at age 45 or younger
- A personal history of bilateral breast cancer (cancer in both breasts)
- 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 personal history of breast cancer at any age and a close family member diagnosed with pancreatic cancer, aggressive prostate cancer or metastatic prostate 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 is first done on the person with breast, ovarian, pancreatic or aggressive prostate cancer.
- If no mutation is found, the cancer was not due to a BRCA1/2 mutation.
- If a BRCA1/2 mutation is found, other family members can be tested for the specific mutation.
Just because one person in the family has a 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 mutation only requires a blood or saliva sample, but the risks and benefits should be considered 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.
Read our perspective on 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.
Under age 25
Every 6-12 months
Every 6-12 months
Only if breast MRI is not available: Every year
Every year (if breast MRI is not available, mammogram)
Ages 30 and older
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 mutations and risk factors for breast cancer
Most risk factors for breast cancer in women likely impact risk in the same way in BRCA1 and BRCA2 carriers and non-carriers.
However, certain reproductive and lifestyle factors may affect risk in BRCA1/2 carriers differently than in non-carriers.
- Having children and a younger age at first childbirth lower the 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 [199,201-204].
- Drinking alcohol and current or recent use of birth control pills increase the risk of breast cancer in the general population. It’s unclear whether these factors affect risk in BRCA1/2 carriers [199,201-202,205,604].
Very low doses of radiation (such as from X-rays) don’t have much, if any, impact on breast cancer risk.
For BRCA1/2 carriers however, there’s some concern the radiation exposure from screening mammography before age 30 may increase breast cancer risk more than for other women .
This issue is under study.
Women who have a BRCA1 or BRCA2 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.
Risk-lowering drugs: tamoxifen and raloxifene
For women at high risk of breast cancer, tamoxifen and raloxifene can lower the risk of :
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.
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 at least 90 percent in women who are BRCA1/2 carriers [147,224-227]
- Add 3-5 years to the lifespan of a 30-year old woman who is a BRCA1/2 carrier [228-229]
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 risks and benefits 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 [147,228,230-235].
The NCCN recommends women with BRCA1/2 mutations, have an 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 .
Prophylactic oophorectomy may also lower the risk of breast cancer [147,236].
Some support groups are tailored to BRCA1 and BRCA2 carriers and people 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 that offers online support for people at higher risk of breast, ovarian or other cancers related 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
|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 gene mutation.
You can also visit the National Institutes of Health’s website to find clinical trials.
Learn more about clinical trials.
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