) In this proposal we request partial support for a special millennium Gordon Research Conference on Mammary Gland Biology to be held at Castelvecchio Pascoli, Lucca, Italy on 21-26 May 2000. This highly successful and well-attended conference is designed to bring together scientists from divergent scientific disciplines who share an interest in the mammary gland. This particular meeting has been designed as a special millennium meeting entitled """"""""Millennium Challenges for Mammary Gland Biology/Breast Cancer Therapy"""""""". The selected topics deal with fundamental biological problems of wide interest with a particular emphasis on areas that are important for breast cancer therapy. This conference is unique in blending basic and applied scientists from academic, clinical and industrial environments, and has previously spawned many multidisciplinary projects that have directly enhanced breast cancer diagnostics and therapeutics. In order to drive forward a new era of breast cancer research in the next millennium, we wish to foster greater relationships between American and European scientists. The mammary gland research community has therefore specifically voted to hold this millennium meeting in Europe. However, in order to be able to undertake this venture of organizing a European venue for the conference, we are seeking funds to pay for the transportation and registration of American speakers. Conference presentations and discussions will not be published or cited, encouraging conferees to present new ideas and information to receptive peers, and all non-speaking conferees will be expected to present posters. The success of the Conference rests on its informal atmosphere structured to facilitate multidisciplinary interaction. All the topics will focus on themes reflecting both basic and clinical aspects of mammary gland development and their relationship with breast cancer. For this reason we are requesting assignment to both NICHD and NCI.