The San Antonio Breast Cancer Symposium is one of the largest international meetings devoted solely to breast cancer research. Basic scientists, translational researchers, clinical investigators and physicians share state-of-the-art information on breast cancer covering almost all the aspects of breast cancer, including prevention, aetiology, diagnosis, molecular biology and treatment. The current report describes relevant therapeutic findings that were presented at the 26 th San Antonio Breast Cancer Conference, held in San Antonio, Texas, USA, in December 2003.