Breast cancer is a major cause of morbidity and mortality among American women for which the need to find new ways to advance its study is recognized. This project addresses a priority identified by the National Action Plan for Breast Cancer. It involves the development of a national referral data base of breast cancer resources. The data base is intended to promote research on breast cancer by centralizing information on the availability of biological specimens which may aid such efforts. Information on currently available resources will be collected and a referral data base which includes the capability to identify approximate numbers of specimens by type of tumor, for example, will be placed on the Internet. The data base will be designed in such a way as to protect the confidentiality of individual specimens. Subsequent to making access to the data base public, a dissemination effort will be undertaken to make the availability of this unique resource widely known within the research and clinical community. Finally, data on the effectiveness of the dissemination campaign and usage statistics for the data base will provide feedback on the utility of this resource.