Genome-wide association studies identify new breast cancer susceptibility genes

Genome-wide association studies (GWAS) provide a powerful method for the identification of commonly inherited, low penetrance susceptibility loci for many diseases, including breast cancer. This approach takes advantage of the known position of millions of commonly inherited genetic variants and is independent of prior knowledge of the position of disease loci. Several GWAS of breast cancer have been completed and several others are ongoing. Taken together, these studies have identified and validated 11 susceptibility loci not previously predicted to contribute to this disease. Several of these alleles also appear to modify breast cancer risk in BRCA1 and BRCA2 mutation carriers. These findings have led to GWAS of BRCA1 and BRCA2 carriers aimed at identifying genetic modifiers of breast cancer risk in these populations. Whereas risks conferred by these loci individually are low, the combined effects may be sufficient for use in risk assessment, screening, and targeted prevention.