A growing number of high profile women have opted for a double mastectomy to protect themselves from breast cancer. Angelina Jolie is the most recent to explain how a blood test showed she carried the risky mutation of the gene BRCA1.
She, Sharon Osbourne and Michelle Heaton have all helped to raise our awareness of the availability of a test for this type of breast cancer. But for us non-celebrities, what are the options for testing and cancer prevention?
What is the breast cancer test?
Doctors take a blood sample to test for mutations in various genes that are linked to breast and ovarian cancer. Though everyone has these genes, it is only when they mutate and develop faults that they are potentially dangerous.
More than 1,000 mutations in the BRCA1 gene have been discovered. The healthy gene supports normal cell growth and also helps mend damaged DNA. It, and another gene - BRCA2 - are part of a family known as 'tumour suppressing genes'. BRCA2 does a similar job to BRCA1 and has around 800 mutations. Many of these mutations have been linked to cancer.
The tests for faults in these genes can predict the risk a person has of developing the inherited form of breast cancer. But this only accounts for around one in 20 cases so even a clear test is no guarantee that you are 100 per cent safe.
Who should be tested?
You should speak to your GP about testing if a member of your close family - such as your mother or sister - has suffered from the disease.
You may also be eligible for a test on the NHS if a number of female members in your extended family have been diagnosed. It's likely here that your doctor will take into account family history and the age of diagnoses in your relatives.
If you are not at risk but want peace of mind, private clinics offer testing that usually includes several hours of consultation and counselling, starting at around £125 an hour - though again it's important to remember that a clear test isn't an all clear for cancer.
Breast cancer risk
The average breast cancer risk for UK women is around 10 per cent. If you have a faulty gene your risk goes up to anything between 50 and 85 per cent.
If you have members of your family with breast cancer, you could have a higher risk. But as not all cases of breast cancer are hereditary, it may have no bearing on your own chances of getting the disease.
What happens after the test
Some women opt to have their breasts removed if they test positive to the faulty gene. Those who do lower their risk of breast cancer caused by mutated genes by around 90 to 95 per cent.
These are major operations and continued monitoring is required to ensure cancer doesn't develop on any left over breast tissue or on the chest. Reconstruction including breast implants is often carried out at the same time.
As this can be a heavy emotional decision, women are usually also offered counselling.
After new guidelines from the National Institute of Clinical Excellence (NICE), the NHS is expected to double the amount of women it offers tests to. But there are fears the 35 genetic testing centres in the UK can't cope with this extra, not the mention the expected rise in women asking for the test after Angelina's revelation.
NICE guidelines don't mean your local NHS trust will immediately start following them to the letter but it should mean that those women whose family history is only suggestive of breast cancer (as opposed to having an extra strong link) will have the right to be tested. Speak to your GP for more information.
[Related: Angelina Jolie praised for publicising details of her preventative double mastectomy]
[Related: Sharon Osbourne: Why I had a double mastectomy]