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Home > Understanding Breast Cancer > Risk Factors and Prevention > BRCA1 and BRCA2

  


BRCA1 and BRCA2

 

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Questions to ask your doctor about genes and inherited breast cancer
Topic Card

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Genetics and Breast Cancer
Fact Sheet

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Research Fast Facts: BRCA1 & BRCA2 
Fact Sheet

Genes and gene mutations

Every cell in your body contains genes. Genes contain the blueprints (genetic code) for your body. For example, they contain the information that determines the color of your eyes. They also contain information that affects how the cells in your body work, such as when cells 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. However, just as with other information in genes, mutations can also be passed on from a parent to a child. Many of these inherited gene mutations have little or no effect on health (good or bad). Others, however, can increase the risk of certain diseases, including cancer. Inherited gene mutations known to increase the risk of breast cancer account for only about five to 10 percent of all breast cancers diagnosed in the U.S.

Learn more about inherited gene mutations.

 

BRCA1 and BRCA2 gene mutations

BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the best-known genes linked to breast cancer risk. 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 or BRCA2 mutation “carrier.”

Like other gene mutations, BRCA1/2 mutations are rare in the general population. In the U.S., between one in 400 and one in 800 people in the general population have a BRCA1/2 mutation. However, prevalence varies by ethnic group. Among Ashkenazi Jewish women and men, about one in 40 carry a BRCA1/2 mutation [26]. 

Prevalence of BRCA1 and BRCA2 mutations among women with breast cancer by ethnic group (U.S.)  

 

BRCA1 

 BRCA2 

Asian American

0.5%

Data not available

African American

1.3-1.4%

2.6%

Caucasian (non-Ashkenazi Jewish)

2.2-2.9%

2.2%

Hispanic

3.5%

Data not available

Ashkenazi Jewish

8.3-10.2%

1.1%

Adapted from National Cancer Institute materials [26-27]. 

 

I’ve been told I have a BRCA1/2 gene mutation — Now what?

If you or a family member has a BRCA1/2 gene mutation, you may have questions about these gene mutations and what they 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 provides information on genetic testing and other topics. Learn more about:

 

BRCA1/2 mutations and breast cancer in women

Women who have a BRCA1/2 gene mutation have an increased risk of breast cancer [28-30]. Women who have a BRCA1 gene mutation have a 50 to 70 percent chance of developing breast cancer by age 70. For BRCA2 carriers, estimates range from 40 to 60 percent [29]. Women in the general population have about an eight percent chance of developing breast cancer by age 70 [4]. (Lifetime risk of breast cancer, defined as risk up to age 85, is about 12 percent [4].)  

This means in a group of 100 women without a mutation, about eight will develop breast cancer by age 70. While in a group of 100 women with a BRCA1/2 mutation, between 40 and 70 will develop breast cancer by age 70. Because these numbers represent average risk, the risk of breast cancer for any one woman with a BRCA1/2 mutation may fall outside this range.  

Together, BRCA1/2 genes are thought to explain a large portion of hereditary breast cancers [26]. Most breast cancers, however, are not hereditary. And, many BRCA1/2 carriers will never have breast cancer [28-30]. A combination of factors likely determines who will develop breast cancer.

Risk of triple negative breast cancer

Women who carry a BRCA1 mutation tend to have breast cancers that are triple negative [113-114]. Triple negative breast cancers are:

Women who carry a BRCA2 mutation tend to have breast cancers that are estrogen receptor-positive (ER+) [113-114].  

Learn about hormone (estrogen and progesterone) receptor status, HER2/neu status and other factors that affect prognosis and treatment.  

Learn more about triple negative breast cancer.  

Learn about molecular subtypes of breast cancer.

Risk of a 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). These tumors usually occur in the opposite (contralateral) breast rather than in the same breast as the first cancer.

For BRCA1/2 mutation carriers, the chance of a contralateral breast cancer 10 years after diagnosis of the first cancer is about 13 to 30 percent compared to about five to 10 percent for breast cancer survivors without a BRCA1/2 mutation [115-120]. The lifetime risk of a second primary contralateral breast cancer is about 30 to 65 percent for BRCA1 mutation carriers and about 30 to 60 percent for BRCA2 carriers [115-120]. 

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For a summary of research studies on BRCA1/2 mutations and breast cancer, visit the Breast Cancer Research section.

 

BRCA1/2 mutations and breast cancer in men 

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Breast Cancer in Men
Fact Sheet

Men can also carry BRCA1/2 mutations and may pass these mutations on to their children.  

Men who have a BRCA2 mutation have an increased risk of breast cancer and may also have an increased risk of prostate cancer [26,28,30,121-122]. The lifetime risk of breast cancer is 1 in 1,000 for men in the general population and about 65 in 1,000 for men with a BRCA2 mutation [119,123].  

Men who have a BRCA1 mutation may also be at increased risk of breast cancer, but this link is less clear [26].  

While only five to 10 percent of breast cancers in women are likely related to gene mutations, up to 40 percent of breast cancers in men may be related to BRCA2 mutations [124]. This means that men who develop breast cancer are more likely to have an inherited gene mutation than women who develop breast cancer.  

Learn more about breast cancer in men.   

 

BRCA1/2 mutations and ovarian cancer

BRCA1/2 mutations increase a woman's risk of ovarian cancer. For women in the general population, the lifetime risk of ovarian cancer is about two percent [125]. However, lifetime risk of ovarian cancer for BRCA1 mutation carriers is estimated at 35 to 70 percent [125]. And, for BRCA2 mutation carriers, this risk is 10 to 30 percent [125].  

Although BRCA1/2 mutation 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, carriers who develop ovarian cancer appear to have better survival than non-carriers. Compared to non-carriers with ovarian cancer, BRCA1 carriers are about 27 percent more likely and BRCA2 carriers are about 51 percent more likely to live five years beyond their diagnosis [240]. One reason for improved survival may be that BRCA-related ovarian cancers appear to have a better chemotherapy response than other ovarian cancers [241-242]. Longer-term data are limited. One study found that after 10 years, overall survival for BRCA1/2 mutation carriers was about the same as for non-carriers [243].  

BRCA1/2 mutation carriers can reduce their risk of both ovarian and breast cancer by having prophylactic oophorectomy (surgical removal of the ovaries) [126]. Learn more about prophylactic oophorectomy 

 

BRCA1/2 mutations & other types of cancer

BRCA1/2 carriers may also have an increased risk of pancreatic cancer, prostate cancer (in male carriers) 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. 

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For a summary of research studies on BRCA1/2 mutations and cancer, visit the Breast Cancer Research section.  

 

Genetic testing for BRCA1/2 mutations

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 are not BRCA1/2 mutation carriers. Genetic testing is recommended only for certain people, including those with [89,244]:

  • A family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin) diagnosed with breast cancer at age 45 or younger
  • A family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin) diagnosed with ovarian cancer at any age
  • A personal or family history of both breast and ovarian cancers on the same side of the family
  • A personal or family history of male breast cancer
  • Ashkenazi Jewish heritage and a family history of breast or ovarian cancer
  • A personal history of breast cancer at age 45 or younger
  • A personal or family history of bilateral breast cancer (cancer in both breasts)

In most cases, testing is first done on the person with breast cancer. If no mutation is found in that person, 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 breast cancer. It is not likely that all family members will have the mutation. For example, if a mother has a BRCA1 or BRCA2 mutation, there is only a 50 percent chance that her child 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 requires just a blood sample, the risks and benefits should be considered before being tested. A health care provider or genetic counselor can help you decide whether genetic testing is appropriate for you or your family members. 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.   

 

Breast cancer screening recommendations for BRCA1/2 carriers

Breast cancer screening tests are used to find cancer in a person without symptoms. For BRCA1/2 carriers, breast cancer screening tests include:

  • Mammography (ma-MAH-gruh-fee) is a screening tool that uses X-rays to create images of the breast. These images, called mammograms (MAM-o-grams), are used to find early signs of breast cancer.
     
  • Clinical breast exam (CBE) is a physical exam done by a health care provider to check the look and feel of the breasts and underarm for any changes or abnormalities (such as lumps).
     
  • Breast magnetic resonance imaging (MRI) uses magnetic fields to create an image of the breast. Breast MRI is more invasive than mammography because a contrast agent is given through an IV before the test. It may be used in combination with mammography.

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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 section.

Ultrasound, which uses sound wave to make images of tissues, may also be used in combination with mammography in some women.

BRCA1/2 mutation carriers should be aware of the warning signs of breast cancer (for women and for men).

Women

BRCA1/2 mutation carriers need to be screened for breast cancer at an earlier age and more frequently than other women. The American Cancer Society (ACS) and National Comprehensive Cancer Network (NCCN) recommend [89-90]: 

 Clinical breast exam 

Mammogram 

Breast MRI and mammogram 

 Under age 25 

Every year

Not recommended 

 Not recommended

 Age 25 and older 

Every 6 to 12 months

Every year

Every year


Men

Although not recommended for all men, breast cancer screening is recommended for [89]:

  • BRCA1/2 carriers
  • Men with a first-degree relative with a BRCA1/2 mutation
  • Men with a strong family history of breast cancer, such as a mother and/or a sister diagnosed at age 40 or younger

NCCN recommends these men [89]:

  • Have a clinical breast exam every six to 12 months, starting at age 25
  • Consider having a mammogram at age 40 (depending on the findings from this first mammogram and the amount of breast tissue, yearly mammograms may be recommended)  

 

BRCA1/2 mutations and risk factors for breast cancer

Many risk factors for breast cancer in women are different from those in men. Learn about risk factors for breast cancer in men.  

Radiation exposure

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 slight [137-139]. However, there is some concern that radiation exposure before age 30 from screening mammography may increase breast cancer risk to a greater degree in BRCA1 and BRCA2 carriers [140]. This issue is under active study.

Other risk factors

Most risk factors for breast cancer likely impact risk in BRCA1/2 mutation carriers just as in non-carriers. For example, exercise and breastfeeding appear to decrease the risk of breast cancer in both mutation carriers and non-carriers [127-128].  

However, certain reproductive and lifestyle factors may affect risk differently for BRCA1/2 mutation carriers than non-carriers. For example:

  • Although having children and a younger age at first birth lower the risk of breast cancer in average women, some studies show no link between these factors and decreased risk among BRCA1 and BRCA2 carriers [127,129-131]. And, a few studies have shown that having more children may actually increase risk in BRCA2 carriers [129-131].
     
  • While starting menstrual periods at an earlier age and current or recent use of birth control pills increase the risk of breast cancer overall, it is unclear whether these factors affect risk in BRCA1 and BRCA2 carriers [127,130-136].  

 

Risk-lowering options for BRCA1/2 carriers

For women who are BRCA1/2 carriers, there are medical options to help lower their high risk of breast cancer.

If you are a BRCA1/2 mutation carrier, talk to your health care provider about the pros and cons of all these options. Remember to take the time to make the 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 [151]:

Tamoxifen is more effective than raloxifene in lowering breast cancer risks and can be used in both pre- and postmenopausal women. However, raloxifene has fewer harmful side effects than tamoxifen (learn more) [151]. Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive (ER+) breast cancers. Neither drug reduces the risk of estrogen receptor-negative (ER-) cancers [151]. 

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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 section.

Learn more about risk-lowering drugs.  

Preventive surgery — prophylactic mastectomy and prophylactic oophorectomy

Prophylactic mastectomy   

Bilateral prophylactic (PRO-fih-LAK-tik) mastectomy is the removal of both breasts to prevent breast cancer. Studies suggest bilateral prophylactic mastectomy can lower the risk of breast cancer in women at high risk by 90 percent or more [245-252]. It may add three to five years to the lifespan of a 30-year-old woman who is a BRCA1/2 carrier [246,253-254].

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 prevent breast cancer. If you are a BRCA1/2 carrier, talk to your health care provider about the risks and benefits of all risk-lowering options to make decisions that are right for you.  

Learn more about prophylactic mastectomy.  

Prophylactic oophorectomy   

Prophylactic oophorectomy is the surgical removal of the ovaries. This procedure [253,255-262]:

  • Lowers the risk of ovarian cancer by 70 to over 90 percent
  • Lowers the risk of breast cancer by 40 to 70 percent

NCCN recommends that women from families with hereditary ovarian cancer syndromes, including BRCA1/2 carriers, have oophorectomy between ages 35 and 40 (or after childbearing is complete) [244].

Learn more about prophylactic oophorectomy.  

 

Support for BRCA1/2 carriers

Some support groups are tailored for BRCA1/2 mutation carriers and those with BRCA-related cancers. Our Support section offers a list of resources to help find a local or on-line support group. For example, FORCE and Sharsheret are organization that have on-line support for women affected by hereditary breast and/or ovarian cancer. 

Komen Support Resources 

  • Our breast care helpline 1-877 GO KOMEN (1-877-465-6636) provides free, professional support services and help finding local support groups. We can also provide support for BRCA1 and BRCA2 carriers and those considering genetic testing. Our trained and caring staff are available to you and your family Monday through Friday from 9:00 a.m. to 10:00 p.m. EST and from 6:00 a.m. to 7:00 p.m. PST.
     
  • Our Message Boards offer online forums to share your thoughts or feelings about subjects related to breast cancer. Our Women at Higher Risk of Breast Cancer forum within the Message Boards offers women at higher risk a place to share their own unique experiences and challenges.  
 

 

 

Finding clinical trials for BRCA1/2 carriers

BreastCancerTrials.org in collaboration with Susan G. Komen® offers a custom matching service that can help you find a clinical trial recruiting people with a BRCA1/2 or other gene mutations. (Learn more about this program.) You can also visit the National Institutes of Health's website to find a clinical trial.  

Learn more about clinical trials.  

Updated 02/05/14

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Inherited Gene Mutations 

Risk-Lowering Drugs 

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Testing for BRCA1 and BRCA2 Mutations 

Preventive Surgery 

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Breast Cancer Screening Recommendations
for Women at Higher Risk