Scientists have confirmed that a common genetic variant -- CASP8 -- offers modest protection against breast cancer, according to a study to be published online in Nature Genetics. The report provides some of the strongest evidence so far that common variants affect the risk of developing breast cancer, and the size of the collaboration sets an important precedent for future studies.
Rare mutations in the genes BRCA1 and BRCA2 significantly raise an individual's risk of breast cancer, but account for only a fraction of the overall variation in genetic risk. More common variants that have a smaller effect on individual risk have been difficult to find, largely due to the size of the studies needed to identify variants of small effect in a convincing manner.
The Breast Cancer Association Consortium, which comprises more than 20 collaborating research groups, examined 9 previously reported breast cancer susceptibility variants in at least 10,000 affected women and 10,000 disease-free women in a study led by Angela Cox. For 8 of the 9 genes, the Consortium reported either no association with breast cancer risk, or marginal evidence for an association. For a variant in the gene CASP8, however, they found a significant association. The particular variant assessed in the study is found in approximately 13% of women of European descent, and is protective, lowering the risk of breast cancer by approximately 10%.
Angela Cox (Sheffield University Medical School, Sheffield, UK)
Abstract available online.
(C) Nature Genetics press release.
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