Four more breast cancer genes have been uncovered by a team of international scientists, a discovery that may rival in importance the cloning of the BRCA2 gene in 1995. Scientists say women with mutated versions of these genes have a pretty low risk of contracting breast cancer, though, and it's unlikely that screening tests for such mutations will be developed.Genetic causes of breast cancer account for 5 to 10 percent of all cases. Lifestyle factors, such as smoking and environmental influences, account for the rest.
Until now, only 25 percent of the genes suspected to cause inherited breast cancer had been identified. The four new genes -- FRFR2, TNRC9, MAP3K1, and LSP1 -- are believed to be fairly common yet account for only four percent of all cases. The genes BRCA1 and BRCA2, in contrast, are not very common but indicate a high risk for disease.
