1. Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health , Bethesda, MD 20892 , USA
2. Department of Clinical Sciences and Community Health, University of Milan , Milan 20122 , Italy
3. Epidemiology Unit, Fondazione IRCCS Ca’ Granda—Ospedale Maggiore Policlinico , Milan 20122 , Italy
4. Cancer Genomics Research Laboratory, Frederick National Laboratory for Cancer Research , Frederick, MD 21701 , USA
5. Information Management Services , Rockville, MD 20850 , USA