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One in five women at greater risk of breast cancer due to newly-discovered faulty genes

A landmark study has revealed found nearly 180 genetic mutations linked to breast cancer: PA Wire/PA Images
A landmark study has revealed found nearly 180 genetic mutations linked to breast cancer: PA Wire/PA Images

One in five women have a significantly higher chance of developing breast cancer due to faults in their genes, researchers have found.

After conducting the largest ever genetic study into breast cancer, scientists found 179 distinct mutations that can be passed down the family tree.

For one in five women, these faulty genes mean they have almost a third higher chance of getting breast cancer, according to research led by Cambridge University. For one in ten, the increased risk is up to 70 per cent, while one per cent are three times more at risk than the rest of the population.

Scientists believe that the new findings could save lives, as blood tests could identify women at greater risk due to their genes. Women, who are currently invited for screening every three years on the NHS, could then be screened more frequently for cancer.

The research, which took place across two studies led by Cambridge University, analysed the DNA of 275,000 women. They discovered almost double the number of genetic variants previously known to cause breast cancer.

After examining 11.8 million genetic ‘spelling mistakes’ in women’s DNA, they confirmed the existence of 107 genetic variants linked to breast cancer and discovered 72 new ones.

They found nine variations affecting the BRCA1 gene, which famously led to actress Angelina Jolie having surgery on her breasts.

From these findings, they concluded that one in five women have a 30 per cent higher risk of breast cancer. Women’s chances of getting breast cancer are normally one in nine. Increasing this by 30 per cent means their chances would be one in seven.

Scientists believe the findings will lead to more frequent screening for women, who are currently screened once every three years on the NHS (PA Wire/PA Images)
Scientists believe the findings will lead to more frequent screening for women, who are currently screened once every three years on the NHS (PA Wire/PA Images)

Professor Doug Easton, one of the lead investigators from Cambridge University, said, according to the Daily Mail: “We have known for a long time that breast cancer runs in families and has a substantial genetic component.

“But judging someone's risk based on their family is a blunt tool. This provides the exact genes which are important, and the way they will be expressed.

“It means some women could be offered more precise screening, using an MRI machine, if their genetic risk is higher, or in future they might be offered preventative drugs like tamoxifen to lower their chances of being diagnosed with breast cancer.”

Researchers say the discoveries explain 39 per cent of the breast cancer risk for women whose mother, sister or daughter has had the disease.

For women who carry the BRCA1 gene, the study offers some hope. Women are told that their risk of breast cancer increases to 70 per cent if they carry the gene, however, scientists found that this increase may only be 35 per cent for some.

Baroness Delyth Morgan, of charity Breast Cancer Now, said: “This is an exciting step forward in our understanding of the genetic causes of breast cancer.

“These gene changes now have the potential to be incorporated into existing models to more accurately predict an individual's risk, and to improve both prevention and early detection of the disease.”