We've all heard of the dreaded "breast cancer gene." But you might be surprised to hear that there are a whopping 18 genetic codes that have been recognized by doctors as common "low risk" breast cancer risk factors. That number was only 13 until several weeks ago, when five new genetic variants were identified. Each of those genes can increase a woman's breast cancer risks by up to 16 percent.
As more mutations are found it increases the chances of combining them in a test for susceptibility to the disease. Such a test could help doctors give advice to women at risk of breast cancer and assist with diagnosis and treatment.
Most of the variants appear to be associated with hormone-sensitive cancers which are stimulated by estrogen. Most breast cancers are hormone sensitive.
To carry out the study, scientists scanned the genetic codes of more than 16,500 women with breast cancer and a family history of the disease, and around 12,000 women without breast cancer.
The findings were published in the journal Nature Genetics.
Professor Nazneen Rahman, from The Institute of Cancer Research in London, said: "Our results now take the total number of gene regions linked to the risk of breast cancer to 18, but we still don't know which genes are causing this increased risk.
