Polygenic susceptibility to breast cancer: current state-of-the-art.

Breast cancer is the most commonly occurring invasive cancer among women and its estimated incidence rate worldwide is approximately 1 million cases annually. Although several breast cancer susceptibility genes have been identified over the past two decades, it is likely that many genes with modest effects are yet to be found. In this review, we discuss the progress that has been recently made with the emergence of empirical genome-wide association studies for breast cancer and the identification of several common, low-penetrance disease alleles at loci that had not been previously implicated as candidates for breast cancer susceptibility. We also discuss the implications of these recent findings for risk prediction, targeted screening and public health interventions, and conclude by discussing the strengths and weaknesses of these studies, and the strategies required to identify additional risk factors for breast cancer.