Université Libre de Bruxelles (ULB) - Institute Jules Bordet, University of California, San Francisco (UCSF), European Organisation for Research and Treatment of Cancer (EORTC), European Organisation for Research and Treatment of Cancer (EORTC), Gustave Roussy Villejuif, Université Paris VI Pierre et Marie Curie - Institut Curie, Catholic University of Louvain (UCL) - CHU Site Sainte-Elisabeth, Institut Curie - Department of Medical Oncology, Noordwest Ziekenhuisgroep, Alrijne Ziekenhuis, Centre Georges-Francois Leclerc, Jeroen Bosch Ziekenhuis, European Institute of Oncology (IEO) IRCCS, Agendia, University of Lausanne - Swiss Institute of Bioinformatics (SIB), Université Libre de Bruxelles (ULB) - Institute Jules Bordet, University of Navarra - Clínica Universidad de Navarra, Kliniken Essen-Mitte - Breast Unit, Università degli Studi di Genova - Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC), Baylor College of Medicine, Institute of Oncology, University of Lausanne - Lausanne University Hospital, Breast International Group Headquarters, Breast International Group Headquarters, University of Texas Health Science Center at San Antonio, Europa Donna-European Breast Cancer Coalition, Merck & Co., Inc., European Organisation for Research and Treatment of Cancer (EORTC), European Organisation for Research and Treatment of Cancer (EORTC), European Organisation for Research and Treatment of Cancer (EORTC), Champalimaud Foundation - Champalimaud Clinical Center and Netherlands Cancer Institute