Cancer risk may be as low as 13% with ‘Jolie gene’
Women warned over drastic surgery
WOMEN with the ‘Angelina Jolie gene’ for breast cancer may want to be cautious before opting for life-changing surgery.
A faulty BRCA1 gene greatly increases a woman’s risk of breast cancer, prompting the Hollywood actress to undergo a mastectomy to remove the danger.
However, a study now shows women with a similar BRCA1 genetic mutation to the film star, or a related faulty BRCA2 gene, may only have a 13 per cent risk of breast cancer.
In fact, their chances of getting diagnosed with breast cancer by the age of 75 ranges from 13 to 76 per cent, scientists estimate, based on their genetic background. The risk varies so much because of other genetic quirks which can help breast tumours form.
Researchers worked the risk out by looking at data for almost 27,000 middle-aged women in the UK, of whom 115 carried the faulty BRCA1 or BRCA2 gene.
These women were monitored for an average of ten years to see if they got ill, to estimate their risk of developing breast cancer. The study looked at women with either of the mutations, and then gave them a score for all the other genetic variations in their DNA which could reduce or increase their chances of cancer. Those with the best overall genetic profile had the best chances.
Dr Amit Khera, a co-author of the study from Harvard Medical School in the US, said many women he sees with the BRCA1 or BRCA2 mutations ‘ have never got breast cancer’, and added: ‘These genes do not mean women are doomed – their DNA is not their destiny.
‘Having a better idea of their overall polygenic risk score could help with really important decisions, such as whether to have a mastectomy, or not to do that and have more frequent screening instead.
‘In the future, this same genetic score for breast cancer and other inherited diseases could help people know their risk decades ahead and make lifestyle changes like losing weight or getting more exercise.’
Around one in 250 women in the UK carry one of the mutations. Miss Jolie had both breasts removed, in a double mastectomy, as well as her ovaries and fallopian tubes to reduce her cancer risk from the faulty BRCA1 gene after her mother died from ovarian cancer at the age of 56.
The study, published in the journal Nature Communications, also sequenced the genes of around 1,900 women with breast cancer and more than 17,000 who did not, in the US.
Researchers estimate that the risk of getting breast cancer in women carrying the faulty genes is anywhere between twice and almost seven times the risk of women with average genes in the general public.
They say a fault in the BRCA genes is important because these genes need to work normally to help DNA repair, preventing mutated cancerous cells from forming tumours.
Although other genetic quirks tend to have a much smaller effect on breast cancer risk, if women have several of these, it can make a difference.
‘DNA is not their destiny’