The recent identification of mutations in breast cancer susceptibility genes has provided the exciting opportunity to help identify women who are at high risk to develop breast cancer. One of the serious impediments to achieving clinical benefits from this information however, is finding and assessing the significance of mutations in these new susceptibility genes. It is imperative that the detection and interpretation of these mutations is coordinated and that this information is made available to as many qualified investigators as possible. There are many sites on the web that contain general as well as scientific information relevant to breast cancer. A partial list of these can be found here. Having participated in the poorly coordinated analysis of other cancer susceptibility genes, we consider it important to create and maintain a central repository for information regarding mutations and polymorphisms. NHGRI also think it critical to make available the reagents necessary to carry out many different techniques for the detection of such mutations. Sponsors: This resource is supported by the National Human Genome Research Institute (NHGRI).