Zhou et al. BMC Cancer 2010, 10:653 http://www.biomedcentral.com/1471-2407/10/653 List of abbreviations DCIS: ductal carcinoma in situ; IHC: immunohistochemistry; CI: Confidence interval; HR: hazard ratio; TMA: tissue microarrays; ER: oestrogen receptor; PR: progesterone receptor; HER2: human epidermal growth factor receptor 2; CK5/6: cytokeratin 5/6; EGFR: epidermal growth factor receptor. Acknowledgements This study was supported by the Swedish Cancer Society (4920-B06-03PCD to FW). We thank Hans Garmo for his initial work in the data analysis. Author details 1Department of Surgical Science, Uppsala University, Uppsala, SE-75105, Sweden. 2Department of Laboratory Medicine, Lund University, Lund, Sweden. 3Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden. 4Department of Oncology, Helsinki University Central Hospital, Finland. 5School of Medicine, Division of Cancer Studies, King’s College, London, UK. Authors’ contributions WZ was responsible for data analyses, manuscript preparation and editing. KJ performed IHC and SISH stainings from the TMAs, and helped to provide expertise in breast cancer pathology. WZ, JC and RMA were involved in pathology review, scoring of stains and contributed substantially to manuscript editing. CB helped with the interpretation of the results and with drafting the manuscript. OA helped to provide expertise in data analyses. FW designed the overall study, compiled and curated the datasets, coordinated the study and helped to draft and finalize the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 17 July 2010 Accepted: 30 November 2010 Published: 30 November 2010 References 1. 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