What are BRCA mutations?
Every one of us has BRCA genes. They are tumour suppressor genes and their job is to repair damage in cells and prevent them from growing and dividing too rapidly. Mutations in these genes can cause cells to become abnormal and grow in an uncontrolled way. This is why genetic mutations can increase a person’s risk of developing certain cancers.
What are the risks?
The tables below show the estimated lifetime risk (up to age 70) for these genetic mutations:
It’s important to note that these mutations increase risk, but are not a guarantee a person will get cancer.
|Type of cancer||General Population||BRCA1||BRCA2|
|Ovarian cancer in women||2%||40-60%||10-20%|
|Breast cancer in women||11%||60-85%||45-60%|
|Breast cancer in men||0.1%||Up to 3%||Up to 12%|
|Prostate cancer||12%||Unknown - likely similar to general population||20-25%|
(There is research suggesting an increased risk of pancreatic cancer for people who have these mutations, but it is ongoing into how much they increase risk.)
How common are BRCA mutations?
In the general population, around 1 in 400 people carry a BRCA1/2 mutation. People of Ashkenazi Jewish descent have a 1 in 40 chance of carrying a BRCA mutation, making them 10 times as likely to carry a BRCA mutation as someone in the general population. Whether you’re a man or a woman, if you have BRCA1/2 mutation then there is a 50% chance of passing the mutation on to your children, whether they are boys or girls.
Why is the Ashkenazi Jewish population at higher risk?
Over 90% of the BRCA mutations found in the Jewish community are one of three “founder mutations”. Researchers have tried to trace the origins of these specific mutations. One theory is that the original mutations occurred around the time of a genetic “bottleneck” around 500-600 years ago, when the population reduced down to as few as 350 people. This was followed by a large expansion in the population which caused the current high frequency of the mutations in the Ashkenazi Jewish population.
Who can get genetic testing?
The eligibility for genetic testing on the NHS testing in the UK is based on national guidelines which use family history of cancer to estimate how likely someone is to be carrying a genetic mutation like BRCA1/2.
With Ashkenazi Jewish ancestry, the chance of carrying a BRCA gene mutation compared to the general population is increased tenfold. This means those with this ancestry can speak to their GP about their risks if they have one or more relatives, on either their mother’s or father’s side, with any of the following cancers:
- Breast cancer
- Ovarian cancer (or fallopian tube/ peritoneal cancer)
- Male breast cancer
- Prostate cancer
- Pancreatic cancer
What is the referral and testing process?
Ask your GP about being referred to your local genetics team. Take along details of your family history (you can use our tool to print out your answers to make this easier). Everyone has the right to choose whether or not to be tested and it’s not a decision to be taken lightly. A genetic counsellor will talk through your risks and options, and help you decide if genetic testing is the right option for you.
If you decide to go ahead with the test, a blood sample will be taken and sent to a specialist lab for testing. The waiting time to get your results will vary from hospital to hospital, but you can request how you receive the results: face-to-face, by telephone or by letter. Once you receive your results you will have the opportunity to talk about what your result means with your genetic counsellor.
Why get tested?
Knowledge is power
- Risk-reducing surgery will lower the risk of ovarian and breast cancer to around 5%.
- Increased surveillance can help spot cancer earlier when it is easier to treat.
- When a BRCA1/2 gene mutation is found, other family members can access testing if they wish.
- For those who have a mutation, fertility options can be accessed through the NHS to prevent BRCA gene mutations being passed to the next generation.
- If someone is diagnosed with cancer, knowledge of whether they have a BRCA gene mutation can give them access to different personalised treatments.
If you have already had cancer
Speak to your oncologist about genetic testing if you have had breast or ovarian cancer, as guidelines are in place outlining that you may be eligible for testing regardless of your family history. This depends on the type of cancer and the age of diagnosis. All women with the most common types of ovarian cancer (non-mucinous epithelial ovarian cancer) are eligible for testing, but whether this is offered within the cancer clinic or the genetics clinic will vary depending on what hospital you are being treated at.