The IMPAKT 2015 Breast Cancer Conference was designed for researchers and clinicians by the Breast International Group (BIG) and the European Society for Medical Oncology (ESMO). The event was held on 7–9 May in Brussels, Belgium, bringing together approximately 525 participants with a special interest in translational science and state-of-the-art applications in the clinical setting. Oncologists, pathologists and scientists collaborated to develop innovative ideas about breast cancer research and to enhance its relevance to patient care. This report highlights the most recent discussions in fundamental research and future clinical perspectives presented by professionals from around the world. It also covers the important issues regarding new technologies for biomarker discovery and the actual path to clinical utility.