1. National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, MD 20782
2. Fred Hutchinson Cancer Research Center, Seattle, WA 98109
3. Institute of Medical Biology, University of Tromsø, N-9035, Tromsø, Norway
4. Oregon Health and Science University, Portland, OR 97239
5. Department of Epidemiology, Zhong Shan Hospital Cancer Center, Shanghai 200052, China
6. Department of Pathology, Shi Dong Hospital, Shanghai 200438, China