A blood test for breast cancer could soon be available and offer an early warning system for all women, not just those with the BRCA genes, scientists said.
Experts found a molecular "switch" in blood samples which increase a women's chances of having breast cancer.
The marker is associated with the BRCA1 breast cancer gene but was also found in other breast cancer patients who went on to develop the disease.
Before this blood test there was no way of predicting the likelihood of breast cancer in someone if the disease did not run in their family.
Around 10% of breast cancers are caused by BRCA1 and BRCA2 gene variants inherited from parents, leaving 90% of cases unexplained.