1. Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20892-7240, USA
2. Department of Preventive Medicine and Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208, USA
3. Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
4. Core Genotyping Facility, NCI-Frederick, SAIC-Frederick Inc., Frederick, MD 21702, USA