Lead author Professor Doug Easton, director of Cancer Research UK's Genetic Epidemiology Unit at the University of Cambridge, said: "While each of these sites have a small impact on breast cancer risk, by finding more of these genes we may be able to develop a test that can predict more reliably a woman's risk of developing breast cancer."

Breast cancer is the most common cancer in the UK with more than 45,500 new cases diagnosed each year.

Lifestyle factors play an important role in influencing the risk of breast cancer, but inherited factors are also important in determining an individual woman's risk of the disease.

Dr Helen George, head of science information at Cancer Research UK, said: "This is by far the largest study of its kind to explore the common genetic variations that contribute to breast cancer risk. This research takes us a step closer to developing a powerful genetic test for the disease. Such a test could help doctors identify women who have an increased breast cancer risk so that they can make informed decisions about how to take steps to reduce their chance of developing the disease."

Source: Cancer Research UK