1Cancer Prevention Research Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., MP-859, Seattle, WA 98109, USA
2Department of Community and Family Medicine, Dartmouth Medical School, Hanover, NH, USA
3Department of Epidemiology, M.D. Anderson Cancer Center, University of Texas, Houston, TX, USA
4Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
5National Cancer Institute Center for Bioinformatics, Bethesda, MD, USA