Estimating cumulative risks for breast cancer for carriers of variants in uncommon genes.

The rapid clinical embrace of next generation multigene cancer predisposition panels has resulted in discovery of DNA variants in genes for which very limited data on penetrance has been published. Evidence for increased risks associated with these genes is often expressed in odds ratios and studies often were conducted on a priori high risk cohorts, i.e. those with young onset disease and/or positive family histories. Despite these limitations, one can estimate cumulative risks, which may be useful for health care providers who are counselling individuals on their results. We present cumulative risks for several under-studied genes and provide generic information that can be extrapolated to data still emerging.