Scientists pinpoint genetic data at the heart of breast cancer risk

Common inherited genetic variants that combine to increase the risk of breast cancer by about a fifth have been identified by scientists.

A huge team of researchers drawn from around the world have uncovered 65 new variants.

On their own, they contribute around 4 per cent of the two-fold heightened risk of women with a strong family history of breast cancer developing the disease.

Adding these variants to the list of 180 already known is thought to account for an estimated 18 per cent of the relative familial risk.

A further ten genetic variants specifically linked to stubborn breast cancers that do not respond to hormone treatment were also found.

They could be responsible for up to 16 per cent of the increased risk of this cancer sub-type in women from affected families.

The Oncoarray Consortium project involved 550 researchers from six continents.

The scientists analysed genetic data from 275,000 women, including 146,000 who had been diagnosed with breast cancer. Professor Doug Easton, one of the lead investigators from Cambridge University, said: “These findings add significantly to our understanding of the inherited basis of breast cancer.

“As well as identifying new genetic variants, we have also confirmed many that we had previously suspected.

“There are some clear patterns in the genetic variants that should help us understand why some women are predisposed to breast cancer and which genes and mechanisms are involved.”

Around 70 per cent of all breast cancers are fuelled by the sex hormone oestrogen.