Breast Cancer Risk Factors: BRCA1 and BRCA2 Inherited Gene Mutations in Women

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 and BRCA2 (BRCA1/2) inherited gene mutations in women. If you have a BRCA1/2 inherited gene mutation, or if a family member has a BRCA1/2 inherited gene mutation, you may have questions about what this means for you. Learn about:

Learn about BRCA1/2 inherited gene mutations in men.

Genes and inherited gene mutations

What are genes?

Every cell in your body has genes. Genes contain the genetic code (blueprints) 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 inherited (passed on from your mother and your father). And you can pass this information on to your children (your daughters and your sons).

What are 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 inherited (passed on from a parent to a child). Inherited gene mutations may also be called germline mutations.

Though gene mutations can be passed down from parent to child, this doesn’t mean if one of your parents has a mutation you will have the mutation. You get one copy of each gene from your mother and one copy from your father.

For example, your mother has two BRCA1 genes. If one of your mother’s BRCA1 genes has a mutation (and her other BRCA1 gene doesn’t have a mutation), there’s a 50% chance you’ll inherit the mutation and a 50% chance you won’t. You get one of your two BRCA1 genes from your mother and it’s random which copy you get.

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% of breast cancers are related to a known inherited gene mutation [6,38].

Learn more about inherited gene mutations.

BRCA1 and BRCA2 inherited gene mutations

Everyone has BRCA1 and BRCA2 (BRCA1/2) 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 increase the risk of cancers in both women and men.

A person who has a BRCA1/2 inherited gene mutation is sometimes called a BRCA1/2 carrier.

How common are BRCA1 and BRCA2 inherited gene mutations?

Like other inherited gene mutations, BRCA1/2 inherited gene mutations are rare in the general population. In the U.S., about 1 in 400 to 1 in 800 people have a BRCA1/2 gene mutation [642].

The proportion of people with a BRCA1/2 gene mutation varies by ethnic group. Among Ashkenazi Jewish women and men, about 1 in 40 have a BRCA1/2 gene mutation [38]. Data on BRCA1/2 mutations in some ethnic groups are limited and more study is needed.

Learn more about people of Ashkenazi Jewish descent and BRCA1/2 gene mutations.

Breast cancer risk in women with a BRCA1 or BRCA2 inherited gene mutation

Women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation have an increased risk of breast cancer [33-39].

BRCA1/2 gene mutations are thought to explain a large portion of hereditary breast cancers [38].

Most breast cancers, however, are not related to inherited gene mutations.

A woman who has a BRCA1/2 inherited gene mutation may be called a BRCA1/2 carrier.

Estimates of breast cancer risk

The lifetime risk of developing breast cancer is [39-40]:

More than 60% for women with a BRCA1/2 inherited gene mutation
13% for women in the general population

This means over a lifetime:

In a group of 100 women with a BRCA1/2 gene mutation, more than 60 will get breast cancer
In a group of 100 women without a BRCA1/2 gene mutation, about 13 will get breast cancer

These numbers are averages. 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%. Many women with a BRCA1/2 gene mutation will never have breast cancer [33-35]. A combination of factors likely causes breast cancer. So, some women with a BRCA1/2 mutation will get breast cancer and many will not.

Learn about risk-lowering options for women with BRCA1/2 inherited gene mutations.

Learn about genetic testing.

Triple negative breast cancer

Women with a BRCA1 gene mutation tend to get breast cancers that are triple negative [38,195-196].

Triple negative breast cancers are:

Estrogen receptor-negative (ER-negative)
Progesterone receptor-negative (PR-negative)
HER2-negative

BRCA2 carriers tend to have breast cancers that are estrogen receptor-positive (ER-positive) [38,195-196].

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

Second primary breast cancer

BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations can increase the risk of a second primary breast cancer (a second breast tumor not related to the first one) [38,197-201].

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

The chance of a contralateral breast cancer 10 years after diagnosis of the first cancer is [38,197-202]:

About 10% to 30% for women with a BRCA1/2 inherited gene mutations
About 5% to 10% for women without a BRCA1/2 inherited gene mutation

The lifetime risk of a second primary contralateral breast cancer is about 40% to 80% for BRCA1/2 carriers [36,54,200].

BRCA1/2 carriers diagnosed with breast cancer in one breast may consider risk-reducing contralateral mastectomy to lower the risk of a second primary breast cancer in the opposite breast [39,54]. This should be discussed with a health care provider.

Learn more about preventive surgery to reduce the risk of breast cancer.

Lowering the risk of breast cancer

Women with a BRCA1/2 inherited gene mutation have options to lower their risk of breast cancer.

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

Ovarian cancer risk in women with a BRCA1 or BRCA2 inherited gene mutation

Women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation may be called BRCA1/2 carriers. BRCA1/2 carriers have an increased risk of ovarian cancer [38-39].

The risk of developing ovarian cancer (up to age 70) is [203]:

35%-70% for women with a BRCA1 inherited gene mutation
10%-30% for women with a BRCA2 inherited gene mutation
Less than 2% 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 worse survival if they’re diagnosed.

BRCA1/2 carriers who get ovarian cancer appear to have better survival than non-carriers in the first 5 years after diagnosis [204-206]. One reason for this improved survival may be that BRCA1/2-related ovarian cancers appear to respond better to chemotherapy than other ovarian cancers [207-208].

Long-term data on survival in BRCA1/2 carriers diagnosed with ovarian cancer are limited.

Lowering the risk of ovarian cancer

BRCA1/2 carriers can reduce their risk of ovarian cancer by having risk-reducing bilateral salpingo-oophorectomy (surgical removal of the fallopian tubes and the ovaries) [54].

Risk-reducing bilateral salpingo-oophorectomy may also lower the risk of breast cancer [54,209].

Learn more about preventive surgery to reduce the risk of ovarian cancer.

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

Risk of other cancers in women with a BRCA1 or BRCA2 inherited gene mutation

Pancreatic cancer

Women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation have an increased risk of pancreatic cancer [38-39,210].

The National Comprehensive Cancer Network (NCCN) doesn’t recommend pancreatic cancer screening for all women with a BRCA1/2 gene mutation [39]. However, the NCCN recommends some women who also have a close family member with pancreatic cancer consider pancreatic cancer screening [39].

Melanoma

Women with a BRCA2 inherited gene mutation (BRCA2 carriers) have an increased risk of melanoma (a type of skin cancer) [38-39].

The NCCN does not have melanoma screening guidelines for BRCA2 carriers. However, it recommends BRCA2 carriers limit sun exposure and consider yearly full-body skin exams to check for signs of melanoma [38-39].

Other cancers

BRCA1/2 gene mutations may also increase the risk of other cancers [38]. 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.

Survival for breast cancers related to BRCA1 and BRCA2 inherited gene mutations

For women with breast cancer, survival is similar for women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation and for those who don’t have a BRCA1/2 gene mutation [204,211-213].

Treatment for breast cancers related to BRCA1 and BRCA2 inherited gene mutations

In general, breast cancers related to a BRCA1 or BRCA2 (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 cancers [214].

Early breast cancer treatment

The PARP inhibitor olaparib (Lynparza) is used to treat some HER2-negative early breast cancers in people with a BRCA1/2 inherited gene mutation [214].

Learn more about olaparib in the treatment of early breast cancer.

Learn more about emerging areas in drug therapies for early breast cancer.

Metastatic breast cancer treatment

The PARP inhibitors olaparib (Lynparza) and talazoparib (Talzenna) are used to treat metastatic breast cancers in some people with BRCA1/2 inherited gene mutations [214]. These drugs are not used to treat breast cancers in people who don’t have BRCA1/2 inherited gene mutations.

Platinum-based chemotherapy drugs (such as carboplatin and cisplatin) are preferred chemotherapy drugs for the treatment of BRCA1/2-related metastatic breast cancers [214].

Learn more about treatments for metastatic breast cancer.

Genetic testing for BRCA1 and BRCA2 inherited gene mutations

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 (BRCA1/2) or other high-risk inherited gene mutation related to breast cancer.

Who should consider genetic testing for BRCA1 and BRCA2 inherited gene mutations?

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), or when genetic testing would help guide breast cancer treatment [39]. This includes people in the table below.

People who should consider genetic testing for BRCA1/2 inherited gene mutations

If you’ve been diagnosed with breast cancer and:

BRCA1/2 genetic testing would help in making treatment decisions
You were diagnosed at age 50 or younger
You were diagnosed with male breast cancer
You were diagnosed with triple negative breast cancer (breast cancer that is estrogen receptor-negative, progesterone receptor-negative and HER2-negative)
You were diagnosed with lobular breast cancer at any age, and have a personal or family history of diffuse gastric cancer
You were diagnosed with 2 or more separate breast cancers involving the same breast or both breasts
You have Ashkenazi Jewish heritage (in at least one grandparent)
A close family member was diagnosed with breast cancer at age 50 or younger
A close family member was diagnosed with ovarian cancer, male breast cancer, pancreatic cancer, or high-risk or metastatic prostate cancer

If you’ve never been diagnosed with breast cancer and have:

A family member with a BRCA1/2 inherited gene mutation (or other inherited gene mutation related to breast cancer)
A family history of cancer and have Ashkenazi Jewish heritage
A close family member diagnosed with breast cancer at age 50 or younger
A close family member diagnosed with ovarian cancer, male breast cancer, pancreatic cancer, or high-risk or metastatic prostate cancer

Source: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment—Breast, Ovarian and Pancreatic Cancer, 2024 [39]

Getting genetic testing for BRCA1 and BRCA2 inherited gene mutations

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 (women and men) can be tested for the specific mutation.

So, just because one person in a family has an inherited gene mutation doesn’t mean everyone in the family has the gene mutation. Only identical twins have the exact same genes. Other family members share some, but not all, of their genes.

Learn more about genetic testing to learn about breast cancer risk.

Learn more about genetic testing to guide breast cancer treatment.

Weighing the risks and benefits of genetic testing for high-risk inherited gene mutations related to breast cancer

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 inherited 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 to learn about breast cancer risk.

Learn more about genetic testing to guide breast cancer treatment.

Breast cancer screening

Breast cancer screening tests are used to find cancer in people with no warning signs or symptoms.

Women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation 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.

For women with a BRCA1/2 inherited gene mutation, the National Comprehensive Cancer Network (NCCN) recommends [39]:

	Clinical breast exam	Mammogram	Breast MRI
Ages 25-29	Every 6-12 months	Only recommended if breast MRI is not available*	Every year*
Ages 30-75	Every 6-12 months	Every year	Every year
* If breast MRI is not available, then mammogram every year ages 25-29

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 high risk of breast cancer, visit the Breast Cancer Research Studies section.

BRCA1 and BRCA2 inherited gene mutations and risk factors for breast cancer

Women with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation may be called BRCA1/2 carriers. Most risk factors for breast cancer in women likely impact risk the same way for women who are BRCA1/2 carriers and women who are non-carriers.

For example, exercise and breastfeeding are linked to a decreased risk of breast cancer in both BRCA1/2 carriers and non-carriers [215-217].

However, breast cancer risk for BRCA1/2 carriers with certain reproductive and lifestyle factors may be different from risk for non-carriers.

For example:

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 [218-221].
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 [222-223].

Radiation exposure

People exposed to very low doses of radiation (such as from X-rays) don’t have much, if any, increased risk of breast cancer [224-225].

While the radiation during mammography is linked to an increased risk of breast cancer over time, this increase in risk is very small [224-225].

However, there’s some concern the radiation exposure from screening mammograms at younger ages may be linked to a higher risk of breast cancer in BRCA1/2 carriers than in other women [226]. This issue is under study.

Breast MRI doesn’t use radiation. The National Comprehensive Cancer Network (NCCN) recommends women ages 25-29 with a BRCA1/2 inherited gene mutation get breast cancer screening with a breast MRI every year [39]. Screening mammography isn’t recommended for these young women unless breast MRI isn’t available [39].

Learn more about breast cancer screening for women with BRCA1/2 inherited gene mutations.

Risk-lowering options

Women with a BRCA1 or BRCA2 (BRCA1 /2) inherited gene mutation have medical options to help lower their risk of breast cancer:

If you have a BRCA1/2 inherited gene mutation, 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

Tamoxifen and raloxifene are FDA-approved for breast cancer risk reduction in women at high risk, including women with BRCA1/2 inherited gene mutations. Tamoxifen and raloxifene are pills.

Both tamoxifen and raloxifene can lower the risk of [227]:

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 [227].

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 [227]. 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

Aromatase inhibitors are hormone therapy drugs used to treat estrogen receptor-positive breast cancer. Aromatase inhibitors are pills.

Exemestane and anastrozole are aromatase inhibitor drugs. Findings from randomized controlled trials have shown each of these drugs may lower the risk of developing breast cancer in postmenopausal women at higher risk [228-229].

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 who do not have breast cancer but are at higher risk of breast cancer.

However, these drugs do not have FDA-approval for use in the risk reduction setting. They’re only FDA-approved for use in breast cancer treatment.

Learn about emerging areas in risk reduction for women at higher risk of breast cancer.

Learn about aromatase inhibitors and breast cancer treatment.

Learn more about risk-lowering drugs.

Preventive surgery — risk-reducing mastectomy and risk-reducing salpingo-oophorectomy

Risk-reducing mastectomy

Risk-reducing bilateral mastectomy (bilateral prophylactic mastectomy) is the removal of both breasts to prevent breast cancer.

Risk-reducing bilateral mastectomy may:

Lower the risk of breast cancer by 90% or more in women with a BRCA1/2 inherited gene mutation (BRCA1/2 carriers) [39,230-232]
Add 3-5 years to the lifespan of a woman who is a BRCA1/2 carrier and gets risk-reducing bilateral mastectomy at age 30 [233-234]

Some women choose risk-reducing bilateral mastectomy 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 risk-reducing mastectomy.

Learn about breast reconstruction after mastectomy.

Risk-reducing salpingo-oophorectomy

Risk-reducing bilateral salpingo-oophorectomy (prophylactic bilateral salpingo-oophorectomy) is the surgical removal of the fallopian tubes and the ovaries to prevent ovarian cancer. It can lower the risk of ovarian cancer by 70% to over 90% [39,233,235-239].

The NCCN recommends women with a BRCA1/2 inherited gene mutation (BRCA1/2 carriers), have a risk-reducing bilateral salpingo-oophorectomy between ages 35-40 (or after childbearing is complete) to lower their risk of ovarian cancer [39].

BRCA2 carriers tend to be diagnosed with ovarian cancer at a later age than BRCA1 carriers [39]. So, BRCA2 carriers who have had risk-reducing bilateral mastectomy may delay risk-reducing bilateral salpingo-oophorectomy until age 40-45 [39]. However, if a family member was diagnosed with ovarian cancer at a young age, risk-reducing bilateral salpingo-oophorectomy for women with a BRCA2 gene mutation may be recommended earlier [39].

Risk-reducing bilateral salpingo-oophorectomy may also lower the risk of breast cancer in BRCA1/2 carriers [39,209,641].

For premenopausal women, risk-reducing bilateral salpingo-oophorectomy causes early menopause.

Learn more about early menopause and how to manage its symptoms.

Learn about fertility options before oophorectomy and find financial assistance fertility treatments.

BRCA1 and BRCA2 inherited gene mutations in men

Men can have BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations and can pass them on to their children.

Men with BRCA1/2 inherited gene mutations have an increased risk of breast cancer and certain other cancers, including prostate cancer [33,35,38-39,192-194,210,240-242].

Learn more about BRCA1/2 inherited gene mutations in men.

Support

Some support groups are tailored to people with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation 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 provides online and telephone support and a resource guide for individuals and caregivers affected by hereditary breast, ovarian and other cancers.

Sharsheret offers online support for Jewish women affected by hereditary breast and/or ovarian cancer.

Susan G. Komen^® Support Resources

Do you need more information about breast cancer risk factors? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support for you and your loved ones including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email helpline@komen.org to get started. All calls are answered Monday through Thursday, 9 a.m. to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
The Komen Breast Cancer and Komen Metastatic (Stage IV) Breast Cancer Facebook groups are places where those with breast cancer and their family and friends can talk with others for friendship and support.
Our fact sheets, booklets and other education materials offer additional information.

Clinical trials

The NCCN encourages people with a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation to consider participating in clinical trials for cancer screening or imaging.

Susan G. Komen^® Patient Care Center

If you or a loved one needs information or resources about clinical trials, the Patient Care Center can help. Contact the Komen Breast Care Helpline at 1-877-465-6636 or email clinicaltrialinfo@komen.org.

Se habla español.

BreastCancerTrials.org in collaboration with Komen offers a custom matching service to help find clinical trials on risk reduction. BreastCancerTrials.org can also help find clinical trials on breast cancer treatment for people with 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.

Learn about insurance and financial assistance programs.

Komen Financial Assistance Program

Susan G. Komen^®created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals.

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) or email helpline@komen.org.

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Updated 06/06/24

TOOLS & RESOURCES

Fact Sheet

Genetics and Breast Cancer

Questions to Ask Your Doctor

Inherited Gene Mutations and Breast Cancer Risk

Research Fast Facts

BRCA Genes and Breast Cancer