What are BRCA1 and BRCA2?

Your body is made up of tiny building blocks called cells. Inside every cell is a set of genes. These genes are the instructions the cell needs to work properly. BRCA1 and BRCA2 are 2 different genes. Everyone has BRCA1 and BRCA2 genes.

BRCA and breast cancer

If a gene is changed, it may not give the correct instructions anymore. A change in a gene is called a gene variant or mutation.

The BRCA1 and BRCA2 genes usually protect us from cancer. A variant in either of these genes reduces the level of protection. Over time, this may mean some types of cancer are more likely to develop.

The risk is highest for breast cancer in women and people assigned female at birth.

BRCA and other cancer types

BRCA1 and BRCA2 gene variants may cause a:

And BRCA2 gene variants may also cause a higher-than-average risk of:

How BRCA genes run in families

Genes are passed from parent to child (inherited) when a sperm and egg join to start a pregnancy (conception).

A woman, or person assigned female at birth, who inherits a BRCA1 or BRCA2 variant has:

  • a high risk of breast and ovarian cancer
  • a 1 in 2 (50%) chance of passing the variant to each of their children.

A man, or person assigned male at birth, who inherits a BRCA1 or BRCA2 variant:

  • may have a slightly higher risk of breast cancer – this is mainly if they have a BRCA2 variant
  • may have a higher risk of prostate and pancreatic cancer – this is mainly if they have a BRCA2 variant
  • has a 1 in 2 (50%) chance of passing the variant to each of their children.

If you do not inherit a BRCA1 or BRCA2 variant, you cannot pass it to any of your children.

Understanding your family history of cancer

Not everyone with a BRCA1 or BRCA2 variant has a history of cancer in their family. But a gene variant is more likely if there is a pattern of cancer in a family.

For example, in the family there may be:

  • several people affected by breast cancer or ovarian cancer
  • people diagnosed with breast cancer before the age of 50
  • people diagnosed with triple negative breast cancer or high-grade serous ovarian cancer
  • diagnosed with breast cancer
  • someone who has had breast cancer in both breasts (bilateral breast cancer) or who has had breast and ovarian cancer.

Families from some ethnic groups are also more likely to carry a gene variant that increases the risk of breast and ovarian cancer. For example, this includes families from an Eastern European or Ashkenazi Jewish (Eastern European Jewish) background.

If you are worried about the pattern of cancer in your family, talk to your GP. If needed, they will refer you to a genetics specialist.

The specialist can give you more advice and information. They will explain whether genetic counselling or genetic testing is likely to be useful.

Genetic testing for a BRCA variant

You may be offered a blood test to check for a BRCA gene variant, if you have:

  • breast cancer at an unusually young age
  • certain types of breast cancer, such as triple-negative breast cancer, at a young age
  • certain types of ovarian cancer, such as high-grade serous ovarian cancer
  • a strong family history of cancer that suggests a BRCA1 or BRCA2 variant is likely
  • a relative who has a BRCA1 or BRCA2 variant.

Understanding genetic test results

If a test shows you have a BRCA1 or BRCA2 variant, this does not mean you will definitely get cancer. But you may have a higher risk of developing some types of cancer.

Your risk of cancer will depend on:

  • your sex assigned at birth (male or female)
  • your age
  • the type of gene variant
  • your family history.

Your genetics specialist will explain this in detail. We have more information about:

Genetic testing may not find a BRCA1 or BRCA2 variant. But you may still have a higher risk of cancer because of the pattern of cancer in your family. 

Depending on your family history, you may be able to have genetic testing for a number of other gene variants. 

You and your family may still be offered cancer screening or treatment to reduce your risk of cancer.

Screening if you have a BRCA variant

Depending on your cancer risk, your genetics specialist may offer you cancer screening. Screening uses tests to find cancer at an early stage when it can be treated most effectively. Your specialist will explain:

  • which screening tests are useful for you
  • when these tests should start
  • how often you will need these tests.

Breast screening

Women, and people assigned female at birth, with a BRCA1 or BRCA2 variant are usually offered tests to look for early signs of breast cancer. We have more about breast screening in our information about inherited breast and ovarian cancer.

Screening for other cancers

People with a BRCA1 or BRCA2 variant are not usually offered screening for ovarian or other cancers. This is because:

  • regular screening tests cannot prevent these cancers
  • there is no clear evidence that screening tests for these cancers can find a cancer early when it is more treatable.

Sometimes screening for other cancer types is offered as part of a clinical trial. Taking part in a clinical trial is your decision. Your doctor or nurse can explain whether a clinical trial is available and the possible risks and benefits of taking part.

Prostate test

There is no screening programme for prostate cancer in the UK. But men, and people assigned male at birth, with a BRCA1 or BRCA2 variant sometimes choose to have a blood test called the PSA test. This test can help diagnose early prostate cancer. Before you have the test, your GP or nurse will talk to you about the benefits and disadvantages of having it.

Risk-reducing treatments and BRCA

Women, and people assigned female at birth, with a BRCA1 or BRCA2 variant may decide to have treatments to reduce their risk of breast and ovarian cancer. This may involve:

  • surgery to remove the breasts (risk-reducing breast surgery).
  • surgery to remove the ovaries and fallopian tubes (risk-reducing bilateral salpingo-oophorectomy)
  • taking a drug for a number of years (chemoprevention).

If you are thinking about risk-reducing treatment, your genetics specialist can give you more information. You may have questions about the best age for you to have surgery or how it may affect you. Sometimes it helps to talk to other people in the same situation.

Symptoms and lifestyle

Cancer is more likely to be successfully treated if it is found at an early stage. Knowing what is normal for your body means you are more likely to recognise any changes that could be a sign of cancer. This means that if you develop cancer, it can be treated as early as possible.

We have more information about possible symptoms of:

We also have general information about the signs and symptoms of cancer that you may find helpful. Symptoms can be caused by things other than cancer. 

Always contact your GP if you have symptoms that are ongoing or unusual for you.

There may also be factors in your lifestyle that affect your cancer risk. There is not always clear evidence about how lifestyle factors affect cancer risk in people with a BRCA1 or BRCA2 variant. But there is strong evidence that a healthy lifestyle can improve your general health and well-being. 

Ask your genetics specialist for advice about your risks. Your healthcare team can give you more information about healthy living.

Planning a family

If you have a BRCA1 or BRCA2 variant, there is a 1 in 2 (50%) chance that any child you have could inherit it from you. You may have questions about this if you are planning to get pregnant or start a pregnancy. Your genetics specialist can give you more information. 

Sometimes pre-implantation genetic testing and fertility treatments can be used to ensure a parent’s gene variant is not passed to a child. The Human Fertilisation & Embryology Authority (HFEA) has information about this.

Finding support

Not everyone with a BRCA1 or BRCA2 variant develops cancer. But it can be difficult to cope with the uncertainty of a higher cancer risk.

You may have questions about your family history, genetic testing and screening. Or you may be thinking about risk-reducing surgery or drugs. There may not always be clear answers. It is important to talk to your genetics specialist, GP or nurse. They will be happy to answer any questions you have.

There is no right or wrong way to cope. But help is there if you need it. If you are struggling to cope with a higher risk of cancer, talking about your feelings and worries may help. You may want to talk to a partner, family member or friend.

Macmillan is also here to support you. If you would like to talk, you can do the following:

About our information

  • References

    Below is a sample of the sources used in our family history and cancer information. If you would like more information about the sources we use, please contact us at  cancerinformationteam@macmillan.org.uk

    Monahan KJ, Bradshaw N, Dolwani S, et al. Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG). Gut. 2020; 69: 411–444. Available from DOI: 10.1136/gutjnl-2019-319915 (accessed October 2022).

    NICE. Familial breast cancer: classification, care and managing breast cancer and related risks in people with a family history of breast cancer. Clinical guideline [CG164]. Last updated: 20 November 2019. Available from https://www.nice.org.uk/guidance/CG164 (accessed October 2022).

    NICE. Molecular testing strategies for Lynch syndrome in people with colorectal cancer. Diagnostics guidance [DG27]. Published: 22 February 2017. Available from https://www.nice.org.uk/guidance/dg27 (accessed October 2022).

    NICE. Testing strategies for Lynch syndrome in people with endometrial cancer. Diagnostics guidance [DG42]. Published: 28 October 2020. Available from https://www.nice.org.uk/guidance/dg42 (accessed October 2022).

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Marc Tischkowitz, Reader and Honorary Consultant Physician in Medical Genetics.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 October 2022
Next review: 01 October 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.