1. Division of Cancer Epidemiology and GeneticsNational Cancer Institute, National Institutes of HealthBethesda MD USA
2. Division of Genome Modifications and CarcinogenesisResearch Program Infection and Cancer, German Cancer Research Center (DKFZ)Heidelberg Germany
3. Department of Chronic Disease PreventionNational Institute for Health and WelfareHelsinki Finland
4. Information Management Services, Inc.Rockville MD USA