G K Gupta1, S Pittaluga1, E W Cowen2. 1. Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, U.S.A. 2. Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD, U.S.A.