Overview
Breast cancer genetic testing
Genetic tests aim to find out if you have inherited (received) certain genes. Genes are messages that give instructions for how cells in your body grow and function. Genes come in pairs, we inherit 1 copy from each parent.
Cancer in the general population
Cancer is a common condition. It affects about 1 in 2 people. Older people are more at risk of getting cancer. The older we get, the less our bodies are able to protect us from cancer.
About 14 out of 100 women are at risk of getting breast cancer in their lifetime.
Most cancers are caused by lifestyle, diet, environments or unknown factors. Some cancers happen because of faulty (mutated) genes inherited from parents.
Inherited breast cancer
Sometimes families are at higher risk of getting breast cancer if they carry faulty genes. Certain genes protect us from cancer by controlling how cells grow.
However, some people can get genetic testing to find out if they have inherited faulty copies of genes such as:
- BRCA1 and BRCA2
- PALB2
- CHEK2
- ATM
- RAD51C and RAD51D
Diagnostic genetic tests
A diagnostic genetic test involves taking a blood sample from you. We will examine your blood to see if you have a faulty gene that is linked with inherited breast cancer, and possibly other cancers.
The results will take up to 10 weeks. We can call you with the results, send them to you, or you can come to the clinic to collect them.
Other genetic tests might be suggested to families based on their individual family history of cancer.
Test results
Negative
A negative test result means we have not found a gene fault in the genes we tested.
If this happens, the chance you have a faulty gene linked to breast cancer is small. However if you have a family history of cancer, there may be other genetic factors involved.
Your genetics clinician might be able to provide recommendations for your relatives affected with cancer. We will not have a genetic test to offer your relatives who have not had cancer.
A negative test also means that your children have not inherited a gene fault in the genes we tested.
Positive
A positive test result means you have a faulty gene. This increases your risk of breast cancer, and possibly other cancers.
Your family might be able to have genetic tests as well, to see if they carry the same faulty gene. We can support you in sharing information with your family so they know how to access genetic testing.
Variant of uncertain significance (VUS)
A VUS test result means there is a fault in a gene, but there’s not enough information to know whether it will increase your risk of breast cancer.
This happens to about 5 out of 100 people. Future medical research might be able to find out if these faults relate to a family history of cancer.
If your results come back with a VUS, we will not be able to make decisions about managing cancer risk for you or family members.
Breast cancer genes
A fault in one of your BRCA1 or BRCA2 genes means that you’re more likely to get cancers such as:
• breast cancer
• ovarian cancer
• pancreatic cancer
• prostate cancer
We have specific information about inheriting a BRCA1 or BRCA2 gene fault, which include the specific cancer risks, and how to manage the risks.
A fault in one of your PALB2 gene means that you’re more likely to get cancers such as:
• breast cancer
• ovarian cancer
• pancreatic cancer
We have specific information about inheriting this gene, specific cancer risks, and how to manage the risks for people with a PALB2 gene fault.
About 4 out of 100 families with a strong history of breast cancer are found to have a faulty CHEK2 gene. The risk of women getting breast cancer if they have a fault in one of their CHEK2 genes is between 20 and 50 out of 100.
We can assess your risk of cancer based on personal, medical, and family history. We also look at hormonal and lifestyle factors. This is done using a risk assessment tool. If you have a gene fault, the risk assessment will help us decide the best screening and management options for you.
CHEK2 is not normally linked with male breast cancer risks. However, research suggests a faulty CHEK2 gene might increase the risk of getting colorectal, prostate and other cancers. These risks are still being studied. Overall these risks are only slightly higher than the risk in the general population.
The current advice will be based on your family history. You can discuss this further with a genetic clinician.
Women are more at risk of breast cancer if they have a fault in one of their ATM genes. There's also a higher risk of getting pancreatic cancer, and for men to get prostate cancer.
The risk of breast cancer in women with a faulty ATM gene is strongly linked with a family history of breast cancer.
We can assess your risk of cancer based on personal, medical, and family history. We also look at hormonal and lifestyle factors. This is done using a risk assessment tool. If you have a gene fault, the risk assessment will help us decide the best screening and management options for you.
The RAD51C gene
- Between 21 and 46 out of 100 women with a RAD51C gene fault get breast cancer.
- Between 11 and 32 out of 100 women with a RAD51C gene fault get ovarian cancer.
The RAD51D gene
- Between 20 and 44 out of 100 women with a RAD51D gene fault get breast cancer.
- Between 13 and 36 out of 100 women with a RAD51D gene fault get ovarian cancer.
We can assess your risk of cancer based on personal, medical, and family history. We also look at hormonal and lifestyle factors. This is done using a risk assessment tool. If you have a gene fault, the risk assessment will help us decide the best screening and management options for you.
Deciding if you should test
Deciding to have diagnostic genetic testing can be a difficult process. You might want to think about:
- Is now the right time to test?
- How will I feel if a gene fault is found?
- Who would I tell about the results?
- How can I manage difficult news?
- What should I do next to manage my risk?
There are no right or wrong answers, but it might be good to think about these questions before you test.
Deciding not to test
Not everyone affected by cancer will choose to have genetic testing. If you decide not to test, you might still be eligible for regular breast screening. Your genetic counsellor will discuss this with you.
More support
Deciding whether to get tested, and waiting for the results, can be challenging. Some people might want to talk through their feelings, coping strategies and other issues before deciding, or after getting their result. Support is available to people with a faulty gene, through:
- your genetics clinician
- the HBOC family service
- the BRCA patient support groups
- your clinical psychologist
- your GP
Your genetics clinician will discuss these with you in more detail so you can decide what the best sources of support will be.
The hereditary breast and ovarian cancer (HBOC) family service
People with faulty genes that put them at risk of breast and ovarian cancer are invited to our HBOC family service clinic. You can ask questions and discuss your management in detail with a team of specialists.
Research studies
Whatever your test result is, there might be an opportunity for you to take part in research. Your genetics clinician or a research nurse will discuss this with you. For more information, contact a member of the research team, phone: 020 7188 2603.
Cancer charities
- Breast Cancer Now provide information and support for people affected by breast cancer.
- Someone Like Me is a service from Breast Cancer Now that puts you in touch with a trained volunteer for advice and support.
- Macmillan Cancer Support provide advice for everyone affected by any cancer.
Resource number: 5053/V2
Last reviewed: November 2024
Next review due: November 2027
