All cancers involve changes in genes. These changes are called mutations. Most cases of breast and ovarian cancer are due to mutations that happen randomly. However, sometimes breast and ovarian cancers run in families, i.e., mutations are inherited. These cases are referred to as hereditary cancers.
Inherited gene mutations for breast and ovarian cancer are most often found in the genes named BRCA1 and BRCA2 (breast cancer genes 1 and 2). The mutations can be passed down to children from either parent. BRCA mutations are associated with increased risk of breast, ovarian, prostate, and pancreatic cancers.
BRCA1 and BRCA2 mutations are not common, so most women will not benefit from genetic testing.
If you come from a family with a history of breast cancer, ovarian cancer, or both, your chance of getting these cancers may be increased, and you may want to consider getting tested for BRCA gene mutations. It is important to note, however, that not all women with a BRCA mutation will develop cancer. Likewise, if you do not have a detectable BRCA mutation, it does not mean that you won't get cancer.
How common are BRCA gene mutations?
Only 5 to 10% of breast cancers are inherited, and most of these are due to detectable mutations in the BRCA1 and BRCA2 genes. 1  Up to 14% of ovarian cancers are thought to be hereditary.
In general, BRCA gene mutations are very rare. Over 99% of women do not have detectable BRCA gene mutations. Only 1 in 300 to 500 women (about one-quarter of one percent of all women) are estimated to have BRCA mutations. 1
An estimated 3,190 females are expected to be diagnosed with breast cancer in 2015. 2  Of those cancers, only 160 – 319 will likely be inherited. This means that the majority of breast cancers are not caused by hereditary factors, and in particular, BRCA1/BRCA2 mutations.
Should I get tested for BRCA1/BRCA2 mutations?
Genetic testing may be a consideration for the small number of women who have been diagnosed with breast cancer at a young age, or whose specific family history patterns are associated with an increased risk for potentially harmful mutations in the BRCA1 or BRCA2 genes.
Your chances of having a BRCA gene mutation might be greater if you have: 
  • A personal history of breast cancer diagnosed before age 50, breast cancer affecting both breasts, or both breast and ovarian cancers
  • A family history of breast cancer in two or more close relatives, such as your parents, brothers, sisters, or children
  • A family member who was diagnosed with breast cancer before age 50
  • A family history of breast cancer in more than one generation
  • A close relative with breast cancer affecting both breasts
  • A family member who has both breast and ovarian cancers
  • A male relative with breast cancer
  • A positive BRCA1 or BRCA2 genetic test in a blood relative
  • Eastern European (Ashkenazi) Jewish ancestry on either side of your family

If you are a woman with a family history of breast or ovarian cancer, you may want to consider a more extensive evaluation by a health professional and counseling by a genetic counselor. Based on your individual situation, this may help you to develop an appropriate strategy for dealing with your cancer risk, which could include genetic testing.


What are my chances of getting breast or ovarian cancer if I have a BRCA mutation?

Not all women with a potentially harmful BRCA mutation get breast or ovarian cancer. If you have a BRCA mutation, your chance of getting breast cancer is about 35 to 84%, and your chance of getting ovarian cancer is 10 to 50%. 1

If you are a man with a BRCA mutation, your chance of getting breast cancer is estimated to be 5-10%. 3


What are the advantages of genetic testing?

The advantages of genetic testing are different for each person. A genetic test may give you more information about your cancer risk, so you can make medical and lifestyle choices accordingly - such as getting more frequent cancer screenings or taking steps to reduce your risk. 

Genetic test results may help to explain why you or members of your family had cancer in the past, and, should you choose to share test results, may provide your family members with useful information. If the results of the genetic test for BRCA are positive, you may be eligible to participate in medical research that could, in the long run, help reduce deaths from breast, ovarian, and prostate cancer.

A negative test result may provide you with a sense of relief and preclude the need for additional procedures or tests beyond routine cancer screening.


What are the disadvantages of genetic testing?

If you are thinking about genetic testing for BRCA gene mutations, you should be informed, both verbally and in writing, about the risks of getting tested. These are some of the factors you should consider before getting tested.

  • Genetic testing for BRCA1 and BRCA2 mutations involves taking a sample of your blood at a doctor's office or lab. Although the medical risks of genetic testing are small, test results may affect your emotions, family relationships, finances, privacy, and medical choices.
  • If your test result is positive, you may feel anxious, angry, or depressed. You may choose to have medical treatment, such as surgery, to try to prevent the cancer, and the treatment could have serious, long-term implications and uncertain effectiveness.
  • If your test result is negative, you may feel guilty because you escaped a disease that affected a loved one. You may also get a false sense of security that you have no chance of getting cancer, when, in fact, your cancer risk is the same as that of the general population (1 in 8 or less, depending on your age and race).
  • Because genetic testing can reveal information about more than one family member, the emotions caused by the results can create tension within families.  The results also can affect personal choices, such as marriage and childbearing.
  • Privacy and confidentiality of genetic test results are additional potential concerns.  HIPAA and GINA are federal acts which address the protection of genetic information.
  • Finally, genetic testing is expensive, costing about $300 to $4,000, depending on the extent of testing. Many insurance plans, including Medicare, cover the cost of the testing for women at high risk, but coverage is unlikely for women not considered to be at high risk. 

What are the limitations of genetic testing?

In addition to benefits and risks, genetic testing has many limitations that are important to consider before you decide to get tested.

  • The BRCA test detects positive mutations in only 25% or less of women with a strong family history and will not provide any useful information for the other 75% or more of women with strong family histories. 4
  • Testing is not 100% accurate. A positive test result can only estimate your risk of getting cancer, but it cannot predict with certainty whether or not you will get cancer. Test results can't determine your exact level of risk, at what age you might develop cancer, how quickly the disease might progress, or how likely you are to die of the disease. 
  • A negative test result doesn't mean that you won't get cancer - only that your risk is the same as that of women without the BRCA mutations, and that you should follow normal screening guidelines. 
  • Genetic test results sometimes are uncertain, or may show abnormalities in the BRCA genes that have not yet been linked to cancer, so they don't provide any information at all about your cancer risk.

Where can I get more information?

A person who is considering genetic testing should speak with a professional trained in genetics before deciding whether to be tested.  Genetic Counselors have special training to help people and families understand and cope with genetic conditions.

For more information on genetic testing, or for help finding a health care professional trained in genetics, refer to the resources and links listed below.





Family Cancer Syndromes , American Cancer Society

Find a Genetic Counselor Near You - Resource Link , National Society of Genetic Counselors


What to Expect When Meeting With a Genetic Counselor , Cancer.Net

BRCA1 and BRCA2: Cancer Risk and Genetic Testing, National Cancer Institute


Cancer Genetics Services Directory of the  National Cancer Institute . A directory of individuals who provide services related to cancer genetics (cancer risk assessment, genetic counseling, genetic susceptibility testing, and others).


Help Me Understand Genetics: Genetic Testing , U.S. National Library of Medicine


Genetic Testing for Hereditary Cancer Syndromes. National Cancer Institute.


Understanding Genetic Testing for Cancer , American Cancer Society


Genetic Testing for Breast Cancer – Video, Mayo Clinic


Genetic testing for breast cancer: Psychological and social impact. Mayo Clinic


Who Should be Tested for the BRCA Gene Mutations?   Imaginis, Breast Cancer Resources





Breast Cancer Risk Assessment Tool . National Cancer Institute.

An interactive tool designed for use by health professionals to estimate a woman's personal risk of developing invasive breast cancer.


Tools and Guidelines, Family (Health) History Resources . Centers for Disease Control and Prevention


Know: BRCA
This online tool is a resource developed to help women understand their risks for having a BRCA1 or BRCA2 gene mutation.


Your Disease Risk . Harvard School of Cancer Prevention/Harvard School of Public Health.
This interactive tool estimates your risk of cancer and provides personalized tips for prevention.



1    Nelson, HD, Huffman, LH, Fu, R, Harris, EL. Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility:  Systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med. 2005;143:362-379.

2    American Cancer Society. Cancer Facts & Figures 2015. Atlanta: American Cancer Society; 2015.

3    Berliner, JF, et al. Risk assessment and genetic counseling for hereditary breast and ovarian cancer: recommendations of the National Society of Genetic Counselors. Journal of Genetic Counselors. 2007;16:241-260.

4    Williams-Jones, B. Be ready against cancer, now: direct-to-consumer advertising for genetic testing. New Genetics and Society. 2006; 25(1), p. 95, citing Carter, R.F. BRCA1, BRCA2 and breast cancer: a concise clinical review. Clinical & Investigative Medicine. 2001; 24(3): 147-57.


Related Pages:

   Breast Cancer (home page)

   Ovarian Cancer (home page) 

   Genomics (home page)

   Breast Cancer in Connecticut

   Breast Cancer Facts

   Connecticut Breast and Cervical Cancer Early Detection Program

   Connecticut Tumor Registry