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  • 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 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 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 breast 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. [4,33].

    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 BRCA1/2 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 [33]. However, prevalence varies by ethnic group. Among Ashkenazi Jewish women and men, about one in 40 carry a BRCA1/2 mutation [33].

    The table below shows how the prevalence of BRCA1/2 mutations varies among breast cancer survivors from different ethnic groups (in alphabetical order).

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

     

    BRCA1

     BRCA2

    African-American

    1%

    3%

    Ashkenazi Jewish

    8-10%

    1%

    Asian-American

    Less than 1%

    Data not available

    Caucasian (non-Ashkenazi Jewish)

    2-3%

    2%

    Hispanic

    4%

    Data not available

    Adapted from National Cancer Institute materials [33]. 

     

    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 [34-36]. Estimates of risk are different for BRCA1 carriers and BRCA2 carriers [33,35-36]:

    • BRCA1 carriers have a 55 to 65 percent chance of developing breast cancer by age 70
    • BRCA2 carriers have about a 45 percent chance of developing breast cancer by age 70

    Women in the general population have about an eight percent chance of developing breast cancer by age 70 [4]. (Lifetime risk of breast cancer, 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 (about 12 by age 85). While in a group of 100 women with a BRCA1/2 mutation, between 45 and 65 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. Note that these risks are not 100 percent. Many women with a BRCA1/2 mutation will never have breast cancer [34-36].

    Together, BRCA1/2 mutations are thought to explain a large portion of hereditary breast cancers [33]. Most breast cancers, however, are not hereditary. A combination of factors likely causes breast cancer.

    Learn about risk-reducing options for women at higher risk.

    Learn about genetic testing.

    Risk of triple negative breast cancer

    Women who have a BRCA1 mutation are at higher risk for triple negative breast cancer, as they tend to have breast cancers that are triple negative [33,123-124]. Triple negative breast cancers are:

    BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [33,123-124].

    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 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 to 30 percent compared to about five to 10 percent for breast cancer survivors without a BRCA1/2 mutation [125-130].

    The lifetime risk of a second primary contralateral breast cancer is about 40 to 65 percent for BRCA1/2 carriers [129]. 

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

     

    BRCA1/2 mutations and cancer in men 

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

    Breast cancer

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    Breast Cancer in Men
    Fact Sheet

    Men who have a BRCA2 mutation have an increased risk of breast cancer [33-34,36,131]. In men, the lifetime risk of breast cancer is 1 in 1,000 for non-carriers and about 65 in 1,000 for BRCA2 carriers [129,132].

    Men who have a BRCA1 mutation may also have an increased risk of breast cancer, but this link is less clear [33].

    While five to 10 percent of breast cancers in women are considered to be due to gene mutations, up to 40 percent of breast cancers in men may be related to BRCA2 mutations [133]. 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.

    Prostate cancer

    Men who have a BRCA2 mutation may also have an increased risk of prostate cancer [33,129,134]. For BRCA2 carriers, the lifetime risk of prostate cancer (up to age 65) is about 15 percent [129].

    Learn about genetic testing.

    BRCA1/2 mutations and ovarian cancer

    BRCA1/2 mutations increase a woman's risk of ovarian cancer [33]. For women in the general population, the lifetime risk of ovarian cancer is less than two percent [135]. However, lifetime risk of ovarian cancer (up to age 70) for BRCA1 carriers is 35 to 70 percent [135]. And, for BRCA2 carriers, this risk is 10 to 30 percent [135].

    Although BRCA1/2 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 [242]. 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 [242]. One reason for improved survival may be that BRCA1/2-related ovarian cancers appear to have a better chemotherapy response than other ovarian cancers [243-244].

    Longer-term data are limited to study survival in BRCA1/2 carriers diagnosed with ovarian cancer. One study found that 10 years after diagnosis, overall survival for BRCA1/2 carriers was about the same as for non-carriers [245].

    Lowering the risk of ovarian cancer

    BRCA1/2 carriers can reduce their risk of both ovarian and breast cancer by having prophylactic oophorectomy (surgical removal of the ovaries) [136].

    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 Studies 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 do not have a BRCA1/2 gene mutation.

    Genetic testing is recommended only for certain people, including those with [246]:

    • A known BRCA1/2 gene mutation in the family
    • A personal history of breast cancer at age 45 or younger
    • A personal history of breast cancer at age 50 or younger and a 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 triple negative breast cancer (breast cancer that is estrogen receptor-negative, progesterone receptor-negative and HER2/neu receptor-negative) diagnosed at age 60 or younger
    • A personal history of ovarian cancer
    • A personal or family history of male breast cancer
    • Ashkenazi Jewish heritage and a personal or family history of breast or ovarian cancer
    • A family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin) diagnosed with breast cancer at age 50 or younger
    • A family member (parent, sibling, child, grandparent, grandchild, uncle, aunt, nephew, niece or first cousin) diagnosed with ovarian cancer at any age

    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 your mother has a BRCA1 or BRCA2 mutation, there is only a 50 percent chance that you 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 just requires a blood sample, the risks and benefits should be considered before testing. 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 is a screening tool that uses X-rays to create images of the breast. These images, called mammograms, 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 Studies section.

    Breast ultrasound, which uses sound waves to make images of tissues, may also be used in combination with mammography in some women, but is not part of breast cancer screening guidelines for BRCA1/2 carriers at this time.

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

    Women 

    BRCA1/2 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 [95-96]:

     Clinical breast exam

    Mammogram

    Breast MRI

     Under age 25

    Every 3 years

    Not recommended 

     Not recommended

     Ages 25 to 29

    Every 6 to 12 months

    Not recommended unless breast MRI is not available (in this case, every year)

    Every year

    Ages 30 and older

    Every 6 to 12 months

    Every year

    Every year


    Men

    Although not recommended for all men, breast cancer screening is recommended for [95]:

    • 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 men that fall into one of the groups above [95]:

    • Be aware of the warning signs of breast cancer in men
    • Have training for breast self-exam starting at age 35
    • Have a clinical breast exam every six to 12 months, starting at age 35
    • 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)
    • Have prostate cancer screening starting at age 40 for BRCA2 carriers (BRCA1 carriers should consider prostate cancer screening starting at age 40)

    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 small [137-139,214].

    However, there is some concern that radiation exposure before age 30 from screening mammography may increase breast cancer risk to a greater degree in BRCA1/2 carriers [140]. This issue is under active study.

    Other risk factors

    Most risk factors for breast cancer likely impact risk in BRCA1/2 carriers just as they impact risk in non-carriers. For example, exercise and breastfeeding appear to decrease the risk of breast cancer in both mutation carriers and non-carriers [141-142,247].

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

    • Although having children and a younger age at first childbirth lower the risk of breast cancer in average women, some studies show no link between these factors and risk among BRCA1/2 carriers [247].
    • Although drinking alcohol and current or recent use of birth control pills increase the risk of breast cancer in average women, some studies show no link between these factors and risk among BRCA1/2 carriers [247].

    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 carrier, talk to 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 [156]:

    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) [156].

    Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive breast cancers. Neither drug reduces the risk of estrogen receptor-negative cancers [156].

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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 Studies 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 at least 90 percent [246,248-252]. It may add three to five years to the lifespan of a 30 year old woman who is a BRCA1/2 carrier [249,253-254].

    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 lower their risk of breast cancer. If you are a BRCA1/2 carrier, talk to your health care provider about the risks and benefits of all your 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 [246,253,255-260]:

    • Lowers the risk of ovarian cancer 70 to over 90 percent
    • Lowers the risk of breast cancer 50 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) [246].

    Learn more about prophylactic oophorectomy.

    Support for BRCA1/2 carriers

    Some support groups are tailored for BRCA1/2 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 organizations 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 and resources. We can also provide support for BRCA1/2 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. ET and from 6:00 a.m. to 7:00 p.m. PT.
    • 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 mutation. You can also visit the National Institutes of Health's website to find a clinical trial.  

    Learn more about clinical trials.  

    Updated 11/10/14

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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