1. From the Division of Medical Oncology A and the Epidemiology Unit, National Cancer Institute, Aviano, Italy; the Departments of Hematology and Dermatology, University of Vienna, Austria; the Albert Einstein Cancer Center, Montefiore Medical Center, New York, NY; the Division of Hematology, Civil Hospital, Brescia, Italy; and the Division of Infectious Diseases B, Amedeo di Savoia Hospital, Turin, Italy.