The Sixth Cambridge Conference on Endocrine and Targeted Manipulation of Breast Cancer was convened in Cambridge, Massachusetts on April 30 and May 1, 2007. The purpose of this multidisciplinary meeting of leaders in clinical and basic research and patient treatment was to assess the most recent data in the field, articulate current best practices, and identify the next steps to advance both patient care and research. Topics included a review of data from major recent and ongoing trials of endocrine treatment in patients with early breast cancer and from studies combining endocrine therapy with other treatment. The current status of breast cancer prevention efforts was examined. Preclinical models of response and resistance, initial efforts to profile tumor response and resistance during endocrine therapy in patients, and new developments in pharmacogenomics were also highlighted. In this article, a synopsis of the key issues discussed, conclusions, and recommendations are summarized; these are presented at greater length in the individual articles and accompanying Open Discussions that comprise the full conference proceedings. In the 2 years since the Fifth Conference, we have gained valuable follow-up data from key trials in early breast cancer, which have helped to clarify both the efficacy and safety and tolerability of the available strategies for endocrine therapy. Observations using endocrine agents in combination with other treatment have been similarly extended. More detailed analysis of preclinical models has improved our understanding of resistance to endocrine therapy, and efforts to explore these and other mechanisms in the clinic are now underway. All of this has and continues to contribute to a growing understanding of how to optimize the use of endocrine agents in both treating and preventing breast cancer.