1. Hematology Department, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain;
2. Centre Hospitalier, Lens and Lille, France;
3. Hematology Division, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico S Matteo, University of Pavia, Pavia, Italy;
4. Royal Hallamshire Hospital, Sheffield, United Kingdom;
5. Universita Milano-Niguarda, Milan, Italy;
6. University of Florence, Florence, Italy;
7. Division of Hematology, Mayo Clinic College of Medicine, Rochester, MN; and
8. Unit of Clinical Epidemiology, Center for the Study of Myelofibrosis, Fondazione IRCCS Policlinico S Matteo, Pavia, Italy