Mutation's presence does not guarantee breast cancer will develop

January 9, 2008 2:30:01 PM PST
A new report in the Journal of the American Medical Association says not all carriers with a genetic mutation will develop breast cancer as previously thought.

The BRCA mutation does raise the risk of breast cancer as earlier studies found -- however, the studies did not look at risks for individuals or particular groups.

But the new research shows there is a wide variation in the risk for families carrying it and suggests that the mutations may be influenced by other genetic factors and possibly the environment.