Genes have an even greater role than first thought in determining whether a person has an increased or a reduced chance of suffering from breast cancer, research suggests.
The study, conducted by scientists from around the world and led by Cancer Research UK, identified one region of DNA that seemed to increase the chance of contracting the disease by around 23%, while another portion of the genetic instructions lowered the risk by up to 11%.
The results, which came from comparing suspect regions of DNA in more than 40,000 women with breast cancer and the same number without the disease, now means the total number of known genetic variants identified as playing a part in altering the risk of breast cancer stands at 13.
Genes - stretches of DNA that provide the instructions for making proteins - are assumed to be responsible after scientists compared genetic samples to identify particular regions or “loci” of DNA that affect risk.
Dr Lesley Walker, director of cancer information at Cancer Research UK, said: ‘If we can identify women who are more likely to get the disease and if we can work out how high this risk is, doctors can make informed decisions about how to stop them getting breast cancer in the first place.’