The promise and limitations of genome-wide association studies to elucidate the causes of breast cancer

With the characterization of the human genome, as well as advances in technology to determine genetic variability across the genomes of populations, there has been focused effort on the identification of cancer susceptibility alleles through the use of genome-wide association studies. These efforts have recently resulted in identification of a susceptibility locus for breast cancer by several groups, although the increases in risk are modest. While genome-wide association studies will probably lead to discoveries of potentially important previously unstudied pathways in cancer etiology, the role of the environment, particularly gene–environment interactions, in breast cancer etiology should not be overlooked.