Genetic Testing for BRCA1 and BRCA2: It’s Your Choice 

1. What are BRCA1 and BRCA2? 

Each year, more than 192,000 American women learn they have breast cancer. 

Approximately 5 to 10 percent of these women have a hereditary form of the disease. 

Changes, called alterations or mutations, in certain genes make some women more 

susceptible to developing breast and other types of cancer. Inherited alterations in the 

genes called BRCA1 and BRCA2 (short for breast cancer 1 and breast cancer 2) are 

involved in many cases of hereditary breast and ovarian cancer. Researchers are 

searching for other genes that may also increase a woman’s cancer risk. 

The likelihood that breast and/or ovarian cancer is associated with BRCA1 or BRCA2 is 

highest in families with a history of multiple cases of breast cancer, cases of both breast 

and ovarian cancer, one or more family members with two primary cancers (original 

tumors at different sites), or an Ashkenazi (Eastern European) Jewish background. 

However, not every woman in such families carries an alteration in BRCA1 or BRCA2, 

and not every cancer in such families is linked to alterations in these genes. 

2. How do alterations in BRCA1 and BRCA2 affect a person’s risk of cancer? 

A woman’s lifetime chance of developing breast and/or ovarian cancer is greatly 

increased if she inherits an altered BRCA1 or BRCA2 gene. Women with an inherited 

alteration in one of these genes have an increased risk of developing these cancers at a 

young age (before menopause), and often have multiple close family members with the 

disease. These women may also have an increased chance of developing colon cancer. 

Men with an altered BRCA1 or BRCA2 gene also have an increased risk of breast cancer 

(primarily if the alteration is in BRCA2), and possibly prostate cancer. Alterations in the 

BRCA2 gene have also been associated with an increased risk of lymphoma, melanoma, 

and cancers of the pancreas, gallbladder, bile duct, and stomach in some men and women.

According to estimates of lifetime risk, about 13.2 percent (132 out of 1,000 individuals) 

of women in the general population will develop breast cancer, compared with estimates 

of 36 to 85 percent (360–850 out of 1,000) of women with an altered BRCA1 or BRCA2 

gene. In other words, women with an altered BRCA1 or BRCA2 gene are 3 to 7 times 

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more likely to develop breast cancer than women without alterations in those genes. 

Lifetime risk estimates of ovarian cancer for women in the general population indicate 

that 1.7 percent (17 out of 1,000) will get ovarian cancer, compared with 16 to 60 percent 

(160−600 out of 1,000) of women with altered BRCA1 or BRCA2 genes. No data are 

available from long-term studies of the general population comparing the cancer risk in 

women who have a BRCA1 or BRCA2 alteration with women who do not have an 

alteration in these genes. Therefore, these figures are estimated ranges that may change 

as more research data are added. 

Some evidence suggests that there are slight differences in patterns of cancer between 

people with BRCA1 alterations and people with BRCA2 alterations, and even between 

people with different alterations in the same gene. For example, one study found that 

alterations in a certain part of the BRCA2 gene were associated with a higher risk for 

ovarian cancer in women, and a lower risk for prostate cancer in men, than alterations in 

other areas of BRCA2. 

Most research related to BRCA1 and BRCA2 has been done on large families with many 

affected individuals. Estimates of breast and ovarian cancer risk associated with BRCA1 

and BRCA2 alterations have been calculated from studies of these families. Because 

family members share a proportion of their genes and, often, their environment, it is 

possible that the large number of cancer cases seen in these families may be partly due to 

other genetic or environmental factors. Therefore, risk estimates that are based on 

families with many affected members may not accurately reflect the levels of risk in the 

general population. 

3. Are specific alterations in BRCA1 and BRCA2 more common in certain 

populations? 

Specific gene alterations have been identified in different ethnic groups. For example, 

among individuals of Ashkenazi Jewish descent, researchers have found that about 

2.3 percent (23 out of 1,000 persons) have an altered BRCA1 or BRCA2 gene. This 

frequency is about 5 times higher than that of the general population. Among people 

with alterations in BRCA1 or BRCA2, three particular alterations have been found to be 

most common in the Ashkenazi Jewish population—two in the BRCA1 gene and one in 

the BRCA2 gene. It is not known whether the increased frequency of these alterations is 

responsible for the increased risk of breast cancer in Jewish populations compared with 

non-Jewish populations. Other ethnic and geographic populations, such as the 

Norwegian, Dutch, and Icelandic people, also have a higher rate of certain genetic 

alterations in BRCA1 and BRCA2. This information about genetic differences between 

ethnic groups may help health care providers determine the most appropriate genetic test 

to select. 
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4. What does a positive BRCA1 or BRCA2 test result mean? 

In a family with a history of breast and/or ovarian cancer, it may be most informative to 

first test a family member who has the disease. If that person is found to have an altered 

BRCA1 or BRCA2 gene, the specific change is referred to as a “known mutation.” Other 

family members can then be tested to see if they also carry that specific alteration. In this 

scenario, a positive test result indicates that a person has inherited a known mutation in 

BRCA1 or BRCA2 and has an increased risk of developing certain cancers, as described 

above. However, a positive result provides information only about a person’s risk of 

developing cancer. It cannot tell whether cancer will actually develop—or when. It is 

also impossible to predict the effectiveness of special screening or preventive medical 

procedures for people with alterations in BRCA1 or BRCA2. Not all women who inherit 

an altered gene will develop breast or ovarian cancer. 

A positive test result may have important health and social implications for family 

members, including future generations. Unlike most other medical tests, genetic tests can 

reveal information not only about the person being tested, but also about that person’s 

relatives. Both men and women who inherit an altered BRCA1 or BRCA2 gene, whether 

or not they get cancer themselves, may pass the alteration on to their sons and daughters. 

However, not all children of people who have an altered gene will inherit the alteration.

5. What does a negative BRCA1 or BRCA2 test result mean? 

A negative test result will be interpreted differently, depending upon whether there is a 

known mutation in the family. If someone in a family has a known mutation in BRCA1 

or BRCA2, testing other family members for that specific gene alteration can provide 

information about their cancer risk. In this case, if a family member tests negative for the 

known mutation in that family, it is highly unlikely that they have an inherited 

susceptibility to cancer. This test result is called a “true negative.” Having a true 

negative test result does not mean that a person will not get cancer; it means that the 

person’s risk of cancer is the same as that of the general population. 

In cases where no known mutation in BRCA1 or BRCA2 has previously been identified 

in a family with a history of breast and/or ovarian cancer, a negative test is not 

informative. It is not possible to tell whether a person has an alteration in BRCA1 or 

BRCA2 that was not identified by the test (a false negative), or whether the result is a 

true negative. In addition, it is possible for people to have an alteration in a gene other 

than BRCA1 or BRCA2 that increases their cancer risk, but is not detectable by this test. 

6. What does an ambiguous BRCA1 or BRCA2 test result mean?

If the test shows a change in BRCA1 or BRCA2 that has not been associated with cancer 

in other people, that person’s test result may be interpreted as ambiguous or uncertain. 

One study found that 10 percent of women who underwent BRCA1 and BRCA2 testing 

had this type of ambiguous genetic change. Because everyone has genetic alterations that 
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do not increase the risk of disease, it is sometimes not known whether a specific change 

affects a person’s risk of developing cancer. As more research is conducted and more 

people are tested for BRCA1 or BRCA2 alterations, scientists will learn more about these 

genetic alterations and cancer risk. 

7. What are the options for a person who tests positive? 

Several approaches are available for managing cancer risk in individuals with alterations 

in their BRCA1 or BRCA2 genes. However, limited data exist on the effectiveness of 

these approaches. 

• Surveillance⎯If cancer develops, it is important to detect it as soon as possible. 

Careful monitoring for symptoms of cancer may be able to catch the disease at an 

earlier stage. Surveillance methods for breast cancer may include mammography and 

a clinical breast exam. Some health professionals also recommend breast self-exams, 

but this surveillance method should not be used in place of clinical exams. Studies 

are currently being conducted to test the effectiveness of other breast cancer screening 

methods in women with an altered BRCA1 or BRCA2 gene. With careful 

surveillance, many cancers will be diagnosed early enough to be successfully treated. 

For ovarian cancer, surveillance methods may include transvaginal ultrasound, 

CA−125 blood testing, and clinical exams. Surveillance can sometimes find cancer at 

an early stage, but it is uncertain whether these methods can reduce a person’s chance 

of dying from ovarian cancer. 

• Prophylactic Surgery⎯This type of surgery involves removing as much of the 

at-risk tissue as possible in order to reduce the chance of developing cancer. 

Preventive mastectomy (removal of healthy breasts) and preventive 

salpingo-oophorectomy (removal of healthy fallopian tubes and ovaries) do not, 

however, offer a guarantee against developing these cancers. Because not all at-risk 

tissue can be removed by these procedures, some women have developed breast 

cancer, ovarian cancer, or primary peritoneal carcinomatosis (a type of cancer similar 

to ovarian cancer) even after prophylactic surgery. 

• Risk Avoidance⎯Behaviors that may decrease breast cancer risk include exercising 

regularly and limiting alcohol consumption. Research results on the benefits of these 

behaviors are based on studies in the general population; the effects of these actions 

in people with BRCA1 or BRCA2 alterations are not yet known. 

• Chemoprevention⎯This approach involves the use of natural or synthetic 

substances to reduce the risk of developing cancer, or to reduce the chance that cancer 

will come back. For example, the NCI-supported Breast Cancer Prevention Trial 

found that the drug tamoxifen reduced the risk of invasive breast cancer by 49 percent 

in women at increased risk for developing the disease. Few studies have been 

performed to test the effectiveness of tamoxifen in women with a BRCA1 or BRCA2 
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alteration. One study found that tamoxifen reduced the incidence of breast cancer by 

62 percent in women with alterations in BRCA2. However, the results showed no 

reduction in breast cancer incidence with tamoxifen use among women with BRCA1 

alterations. Additional chemoprevention studies with tamoxifen and other substances 

in women with an altered BRCA1 or BRCA2 gene are anticipated. 

• Gene Therapy⎯At present, altered BRCA1 and BRCA2 genes cannot be repaired. 

Some day it may be possible to fix or manipulate the genes or sets of genes that 

increase one’s risk of cancer.

8. What are some of the benefits of genetic testing for breast and ovarian cancer risk? 

There can be benefits to genetic testing, whether a person receives a positive or a 

negative result. The potential benefits of a negative result include a sense of relief and 

elimination of the need for special preventive checkups, tests, or surgeries. A positive 

test result can bring relief from uncertainty and allow people to make informed decisions 

about their future, including taking steps to reduce cancer risk. In addition, many people 

are able to participate in medical research that may, in the long run, decrease the risk of 

death from breast cancer. 

9. What are some of the risks of genetic testing for breast and ovarian cancer risk? 

The direct medical risks of genetic testing are very small, but test results may have an 

impact on a person’s emotions, social relationships, finances, and medical choices. 

People who receive a positive test result may feel anxious, depressed, or angry. They 

may choose to undergo preventive measures that have serious long-term implications and 

whose effectiveness is uncertain. People who receive a negative test result may 

experience “survivor guilt” caused by avoiding a disease that affects a loved one. They 

may also be falsely reassured that they have no chance of developing cancer, even though 

people with a negative test result have the same cancer risk as the general population. 

Because genetic testing can reveal information about more than one family member, the 

emotions caused by test results can create tension within families. Test results can also 

affect personal choices, such as marriage and childbearing. Issues surrounding the 

privacy and confidentiality of genetic test results are additional potential risks (see 

below). 

10. What can happen when genetic test results are placed in medical records? 

Clinical test results are normally included in a person’s medical records, and the inclusion 

of genetic test results in a patient’s records may have serious implications. For example, 

when applying for medical, life, or disability insurance, people may be asked to sign 

forms that give the insurance company permission to access their medical records. The 

insurance company may take genetic test results into account when making decisions 

about coverage. An employer may also have the right to look at an employee’s medical 
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records. Individuals considering genetic testing must understand that when test results 

are placed in their medical records, the results might not be kept private. 

Some physicians keep test results out of medical records. However, even if genetic test 

results are not included in a person’s medical records, there may still be some risk of 

discrimination. Information about a person’s genetic profile can sometimes be gathered 

from that person’s family medical history. 

11. What is genetic discrimination, and what laws protect people from this type of 

discrimination? 

Genetic discrimination occurs when people are treated differently by their insurance 

company or employer because they have a gene alteration that increases their risk of a 

disease, such as cancer. People who undergo genetic testing to find out whether they 

have an alteration in their BRCA1 or BRCA2 gene may be at risk for genetic 

discrimination. 

A positive genetic test result may affect a person’s insurance coverage, particularly their 

health insurance. A person with a positive result may be denied coverage for medical 

expenses related to their genetic condition, dropped from their current health plan, or 

unable to qualify for new insurance. Some insurers view the affected individual as a 

potential cancer patient whose medical treatment would be costly to the insurance 

company. 

The Health Insurance Portability and Accountability Act (HIPAA) of 1996 provides 

some protection for people who have employer-based health insurance. The Act 

prohibits group health plans from using genetic information as a basis for denying 

coverage if a person does not currently have a disease. However, the Act does not 

prohibit employers from refusing to offer health coverage as part of their benefits, or 

prevent insurance companies from requesting genetic information. 

In 2000, the Department of Health and Human Services released the HIPAA National 

Standards to Protect Patients’ Personal Medical Records. This regulation covers medical 

records maintained by health care providers, health plans, and health care clearinghouses. 

Although the standards are not specific to genetic information, they provide the first 

comprehensive Federal protection for the privacy of health information. 

A person who tests positive for a BRCA1 or BRCA2 alteration may also experience 

genetic discrimination in the workplace if an employer learns about the test result. 

Although there are currently no Federal laws specific to genetic nondiscrimination, some 

protection from discrimination by employers is offered through the Americans with 

Disabilities Act of 1990 (ADA). In 1995, the Equal Employment Opportunity 

Commission (EEOC) expanded the definition of “disabled” to include individuals who 

carry genes that put them at higher risk for genetic disorders. The extent of this 

protection, however, has not yet been tested in the courts. 
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Several states also have laws that address genetic discrimination by employers and health 

insurance companies. The degree of discrimination protection varies from state to state. 

Therefore, the decisions that people make about genetic testing while living in one state 

may have repercussions in the future if they move to another area. 

12. How are the tests for BRCA1 or BRCA2 performed?

Testing for alterations in a person’s BRCA1 or BRCA2 gene is done on a blood sample. 

The person’s blood is drawn in a laboratory, doctor’s office, hospital, or clinic, and the 

blood sample is sent to a laboratory to check for alterations in the BRCA1 and/or BRCA2 

genes.

13. How much does testing cost and how long does it take to get the results? 

The cost for genetic testing can range from several hundred to several thousand dollars. 

Insurance policies vary with regard to whether the cost of genetic testing is covered. 

As addressed above, because the results of genetic tests can affect a person’s health 

insurance coverage, some individuals may not want to use their insurance to pay for 

testing. Some people may choose to pay out-of-pocket for the test, even when their 

insurer would be willing to cover the cost. To protect their privacy, some may not even 

want their insurer to know they are thinking about genetic testing. Others may decide to 

ask their insurance company to cover these costs. People who are considering genetic 

testing may want to find out more about their particular insurance company’s policies and 

the privacy protection laws in their state before submitting the charge for the test. 

From the date that blood is drawn, it can take several weeks or months for test results to 

become available. The length of time depends on the tests performed and other factors. 

Individuals who decide to get tested should check with their doctor or genetic counselor 

to find out when test results might be available.

14. What factors increase the chance of developing breast and/or ovarian cancer? 

The following factors have been associated with increased breast and/or ovarian cancer 

risk. It is not yet known exactly how these factors influence risk in people with BRCA1 

or BRCA2 alterations. 

• Age⎯The risk of breast and ovarian cancers increases with age. Most breast and 

ovarian cancers occur in women over the age of 50. Women with an altered BRCA1 

or BRCA2 gene often develop breast or ovarian cancer before age 50. 

• Family History⎯Women who have a first-degree relative (mother, sister, or 

daughter) or other close relative with breast and/or ovarian cancer may be at 

increased risk for developing these cancers. In addition, women with relatives who 

have had colon cancer are at increased risk of developing ovarian cancer. 
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• Medical History⎯Women who have already had breast cancer are at increased risk 

of developing breast cancer again, or of developing ovarian cancer. Women who 

have had colon cancer also have an increased risk of developing ovarian cancer. 

• Hormonal Influences⎯Estrogen is naturally produced by the body and stimulates 

the normal growth of breast tissue. It is suspected that excess estrogen may 

contribute to breast cancer risk because of its natural role in stimulating breast cell 

growth. Women who had their first menstrual period before the age of 12 or 

experienced menopause after age 55 have a slightly increased risk of breast cancer, as 

do women who had their first child after age 30. Each of these factors increases the 

amount of time a woman’s body is exposed to estrogen. Removal of a woman’s 

ovaries, which produce estrogen, reduces the risk of breast cancer. 

• Birth Control Pills (Oral Contraceptives)⎯Most studies show a slight increase or 

no change in breast cancer risk in women taking birth control pills. Some studies 

suggest that a woman who has taken birth control pills for a long period of time, and 

began taking them at an early age or before her first pregnancy, has a small increase 

in her risk for developing breast cancer. In contrast, taking birth control pills may 

decrease a woman’s risk of ovarian cancer. 

• Hormone Replacement Therapy⎯A woman’s risk for developing breast cancer 

may be increased by hormone replacement therapy (HRT), especially when it is used 

for a long period of time. Doctors may prescribe HRT to reduce the discomfort from 

symptoms of menopause, such as hot flashes. Some evidence suggests that women 

who use HRT after menopause may also have a slightly increased risk of developing 

ovarian cancer. HRT may have positive health effects as well, such as lowering a 

woman’s risk of heart disease and osteoporosis. These protective effects diminish 

after a woman discontinues therapy. The risks and benefits of HRT should be 

carefully considered by a woman and her health care provider. 

• Dietary Fat⎯Although early studies suggested a possible association between a 

high-fat diet and increased breast cancer risk, more recent studies have been 

inconclusive. It is not yet known whether a diet low in fat will lower breast 

cancer risk. 

• Physical Activity⎯Studies of the relationship between physical activity and breast 

cancer have had mixed results. However, some studies suggest that regular exercise, 

particularly in women age 40 and younger, may decrease breast cancer risk. 

• Alcohol⎯Alcohol use may increase breast cancer risk, but no biological mechanism 

for the relationship between alcohol and breast cancer risk has been established. 

• Environmental Factors⎯Exposure of the breast to ionizing radiation, such as 

radiation therapy for Hodgkin lymphoma or other disorders, is associated with an 
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increased risk of breast cancer, especially when the exposure occurred at a young age. 

Evidence for the effect of occupational, environmental, or chemical exposures on 

breast cancer risk is limited. For example, there is some evidence to suggest that 

organochlorine residues in the environment, such as those from insecticides, might be 

associated with an increase in breast cancer risk. However, the significance of this 

evidence has been debated. Scientific research is currently in progress to study the 

effects of various environmental factors on breast cancer risk. 

15. Where can people get more information about genetic testing for cancer risk? 

A person who is considering genetic testing should speak with a professional trained in 

genetics before deciding whether to be tested. These professionals may include doctors, 

genetic counselors, and other health care workers trained in genetics (such as nurses, 

psychologists, or social workers). For more information on genetic testing or for help 

finding a health care professional trained in genetics, contact the National Cancer 

Institute’s Cancer Information Service (CIS) at 1–800–4–CANCER (1−800−422−6237) 

(see below). The CIS can also provide information about clinical trials (research studies 

with people) and answer questions about cancer. 

References

Aziz S, Kuperstein G, Rosen B, et al. A genetic epidemiological study of carcinoma of the 

fallopian tube. Gynecologic Oncology 2001; 80(3):341−345. 

The Breast Cancer Linkage Consortium. Cancer risks in BRCA2 mutation carriers. Journal of 

the National Cancer Institute 1999; 91(15):1310−1316. 

Brekelmans CTM, Seynaeve C, Bartels CCM, et al. Effectiveness of breast cancer surveillance 

in BRCA1/2 gene mutation carriers and women with high familial risk. Journal of Clinical 

Oncology 2001; 19(4):924–930. 

Fisher B, Constantino JP, Wickerham DL, et al. Tamoxifen for prevention of breast cancer: 

Report of the National Surgical Adjuvant Breast and Bowel Project P−1 Study. Journal of the 

National Cancer Institute 1998; 90(18):1371–1388. 

Garber J. A 40-year-old woman with a strong family history of breast cancer. Journal of the 

American Medical Association 1999; 282(20):1953–1960. 

Hartge P, Struewing JP, Wacholder S, Brody LC, Tucker MA. The prevalence of common 

BRCA1 and BRCA2 mutations among Ashkenazi Jews. American Journal of Human Genetics

1999; 64:963–970. 
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King M, Wieand S, Hale K, et al. Tamoxifen and breast cancer incidence among women with 

inherited mutations in BRCA1 and BRCA2. Journal of the American Medical Association 2001; 

286(18):2251−2256. 

Kodish E, Wiesner GL, Mehlman M, Murray T. Genetic testing for cancer risk: How to 

reconcile the conflicts. Journal of the American Medical Association 1998; 279(3):179–181. 

Malone KE, Daling JR, Thompson JD, et al. BRCA1 mutations and breast cancer in the general 

population: Analyses in women before age 35 years and in women before age 45 years with 

first-degree family history. Journal of the American Medical Association 1998; 279(12):922–

929. 

Martin AM, Weber BL. Genetic and hormonal risk factors in breast cancer. Journal of the 

National Cancer Institute 2000; 92(14):1126–1135. 

Newman B, Mu H, Butler LM, Millikan RC, Moorman PG, King MC. Frequency of breast 

cancer attributable to BRCA1 in a population-based series of American women. Journal of the 

American Medical Association 1998; 279(12):915–921. 

Peshkin BN, DeMarco TA, Brogan BM, Lerman C, Isaacs C. BRCA1/2 testing: Complex 

themes in result interpretation. Journal of Clinical Oncology 2001; 19(9):2555–2565. 

Rebbeck TR. Prophylactic oophorectomy in BRCA1 and BRCA2 mutation carriers. Journal of 

Clinical Oncology 2000; 18(21s):100s−103s. 

Thompson D, Easton E, on behalf of the Breast Cancer Linkage Consortium. Variation in cancer 

risks, by mutation position, in BRCA2 mutation carriers. American Journal of Human Genetics

2001; 68(2):410−419. 

Warner E, Foulkes W, Goodwin P, et al. Prevalence and penetrance of BRCA1 and BRCA2 

gene mutations in unselected Ashkenazi Jewish women with breast cancer. Journal of the 

National Cancer Institute 1999; 91(14):1241−1247. 

Welch HG, Burke W. Uncertainties in genetic testing for chronic disease. Journal of the 

American Medical Association 1998; 280(17):1525–1527. 

# # # 

Related NCI materials and Web pages: 

• Cancer Genetics Home Page (http://www.cancer.gov/cancertopics/preventiongenetics-causes/genetics)

• What You Need To Know AboutTM Breast Cancer

(http://www.cancer.gov/cancertopics/wyntk/breast) 
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• What You Need To Know AboutTM Ovarian Cancer

(http://www.cancer.gov/cancertopics/wyntk/ovary)

For more help, contact: 

NCI’s Cancer Information Service 

Telephone (toll-free): 1–800–4–CANCER (1–800–422–6237) 

TTY (toll-free): 1–800–332–8615

LiveHelp® online chat: https://cissecure.nci.nih.gov/livehelp/welcome.asp

This fact sheet was reviewed on 2/6/02