1. Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
2. Department of Pathology, University of Pittsburgh, Pittsburgh, PA
3. Division of Hematopathology, Mayo Clinic, Rochester, MN
4. Department of Pathology, Centro de Investigación Biomédica en Red de Oncología, Hospital Universitario Fundación Jimenez Diaz, Madrid, Spain