Research published last week in Nature Genetics reports the discovery of two new genes which alter a woman's risk of developing breast cancer. The study, led by Cancer Research UK, was a collaboration between more than 100 scientists across 16 countries. It brings the total number of known genetic variants which alter breast cancer risk to 13.
Professor Doug Easton from the University of Cambridge, UK, along with colleagues from around the world, scanned the entire genetic code of 400 female breast cancer patients in order to locate regions of interest. These regions were then tested in 40,000 women with breast cancer and 40,000 women without. Two genes were identified that are believed to influence a woman's risk of developing breast cancer. One gene may elevate breast cancer risk by up to 23 per cent in people who carry two faulty copies of that stretch of DNA (with a 12 per cent increase in risk in those with one faulty copy). The other gene lowers risk by as much as 11 per cent in those who carry two faulty copies (and by four per cent in those who carry only one).
Breast cancer is the most common cancer in the UK. Around five to 10 per cent of the 45,500 new cases each year are thought to have a genetic cause. The remaining 90-95 per cent are accounted for by lifestyle and environmental factors. Commenting on the new findings, Dr Lesley Walker, director of cancer information at Cancer Research UK, said: 'This study brings us a step closer to creating a powerful genetic test for breast cancer.'