1. Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco
2. Cancer Prevention Institute of California, Fremont3Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California
3. Cancer Prevention Institute of California, Fremont
4. Departments of Pathology and Dermatology, University of California, San Francisco
5. Department of Dermatology, Stanford University School of Medicine, Stanford, California
6. Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California6Health Sciences, Exponent, Inc, Menlo Park, California