Footnotes

• Funding The German study was supported by the Dietmar Hopp Foundation, the German Cancer Research Center DKFZ and the Helmholz Association. The Italian study was funded by grants from Fondazione Italiana per la Ricerca sul Cancro (Special Project ‘Hereditary tumors’), Associazione Italiana per la Ricerca sul Cancro (4017), Ministero della Salute (RFPS-2006-3-340203; Extraordinary National Cancer Program 2006, ‘Alleanza Contro il Cancro’; ‘Progetto Tumori Femminili’), Ministero dell'Università e Ricerca (RBLAO3-BETH) and Istituto Superiore di Sanità (526D/41) and by funds from Italian citizens who allocated the 5×1000 share of their tax payment in support of the Fondazione IRCCS Istituto Nazionale Tumori, according to Italian laws (INT-Institutional strategic projects ‘5×1000’). In the Australian study, infrastructure support for the Melbourne Collaborative Cohort Study recruitment and follow-up is provided by The Cancer Council Victoria, while cohort recruitment was partly funded by VicHealth. This work, using the Melbourne Collaborative Cohort Study, was supported by the Australian National Health and Medical Research Council (grants 209057, 251533 and 396414). MCS is a Senior Research Fellow of the National Health and Medical Research Council (Australia) and Group Leader of the Victorian Breast Cancer Research Consortium. The Spanish study was partially supported by ‘Red de Investigación en Cáncer RD06/0020/1160’, Spanish Ministry of Science and Innovation (FIS PI08 1120 and SAF2010-20493) and Fundación Mutua Madrileña.

• Competing interests None.

• Ethics approval University of Heidelberg; Fondazione IRCCS Istituto Nazionale Tumori, Milan; University of Melbourne; Queensland Institute of Medical Research; Centro Nacional de Investigaciones Oncologicas, Madrid.

• Provenance and peer review Not commissioned; externally peer reviewed.