Toi et al. BMC Cancer 2010, 10:56 http://www.biomedcentral.com/1471-2407/10/56 We are grateful to Jodi Weidler, Yolanda Lie, Ahmed Chenna, Ellen Paxinos, Agnes Pacquet, Rajiv Dua, Elicia Penuel, Jeannette Whitcomb and Gordon Parry for critical input and helpful discussions. We would like to thank members of the Monogram Biosciences operations team as well as the clinical laboratory personnel for their contributions to the development of the VeraTag assay system. We would also like to thank and acknowledge the patients who participated in this study, without whom new insights into the biology of breast cancer would not be possible. Author details 1Faculty of Medicine, Kyoto University, Kyoto, Japan. 2Department of Research and Development, Monogram Biosciences, Inc., South San Francisco, CA, USA. 3Department of Clinical Research, Monogram Biosciences, Inc, South San Francisco, CA, USA. 4Division of Clinical Trials and Research and Department of Surgery, Tokyo Metropolitan Cancer and Infectious Disease Center, Komagome Hospital, Tokyo, Japan. 5Division of Breast Oncology, National Kyushu Cancer Center, Fukuoka, Japan. 6Breast Surgical Oncology, St Luke’s International Hospital, Tokyo, Japan. 7Department of Breast Oncology, Aichi Cancer Center Hospital, Aichi, Japan. 8Department of Surgery, National Hospital Organization, Osaka National Hospital, Osaka, Japan. 9Department of Breast Oncology, National Hospital Organization, Shikoku Cancer Center, Matsuyama, Japan. 10Department of Biostatistics and Epidemiology, Yokohama City University Medical Center, Yokohama, Japan. Authors’ contributions MT carried out study design, clinical study coordination, hypothesis generation, supervision of data analyses, and data interpretation. Carried out JS data quality assurance, data analysis, and data interpretation. WH participated in central IHC re-tests, oversight of HERmark assay performance, data interpretation. SS participated in study design, data management, clinical trial. JW carried out HERmark assay design and supervision of HERmark data generation. XJ and YT carried out HERmark assay performance and quality assurance. SO, SN, HI, NM, and KA participated in clinical trial. SM carried out biostatistical analysis, supervision of data analysis, and data interpretation. CP conceived of assay design and supervised all HERmark assay development, data interpretation. MB carried out study design, hypothesis generation, supervision of data analyses, data interpretation. MT and MB have manuscript authorship. All authors read and approved the final manuscript. Competing interests JS, WH, JW, XJ, YT, CP, and MB are employees and stockholders in Monogram Biosciences. Received: 15 April 2009 Accepted: 23 February 2010 Published: 23 February 2010 References 1. Burstein HJ: The distinctive nature of HER2-positive breast cancers. N Engl J Med 2005, 353:1652-4. 2. Cobleigh MA, Vogel CL, Tripathy D, Robert NJ, Scholl S, Fehrenbacher L, Wolter JM, Paton V, Shak S, Lieberman G, Slamon DJ: Multinational study of the efficacy and safety of humanized anti-HER2 monoclonal antibody in women who have HER2-overexpressing metastatic breast cancer that has progressed after chemotherapy for metastatic disease. J Clin Oncol 1999, 17:2639-48. 3. Eppenberger-Castori S, Kueng W, Benz C, Caduff R, Varga Z, Bannwart F, Fink D, Dieterich H, Hohl M, Müller H, Paris K, Schoumacher F, Eppenberger U: Prognostic and predictive significance of ErbB-2 breast tumor levels measured by enzyme immunoassay. J Clin Oncol 2001, 19:645-56. 4. 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