1. Italian Network for Quality Assessment of Tumor Biomarkers-Coordinating Unit, National Cancer Institute, Bari, Italy
2. United Kingdom National External Quality Assessment Service Immunocitochemistry and Fluorescence In Situ Hybridization Histopathology, University College London, London, United Kingdom
3. Italian Network for Quality Assessment of Tumor Biomarkers-Biostatistics Unit, Institute of Medical Statistics and Biometry, University of Milan, Milan, Italy
4. Italian Network for Quality Assessment of Tumor Biomarkers-Biostatistics Unit, Istituto Nazionale dei Tumori, Milan, Italy