1. Department of Statistics; Sookmyung Women's University; Seoul Korea
2. Division of Cancer Epidemiology and Genetics; National Cancer Institute; National Institutes of Health; Department of Health and Human Services; Rockville Maryland United States of America
3. Information Management Services, Inc.; Rockville Maryland United States of America
4. Department of Biostatistics; Bloomberg School of Public Health; Johns Hopkins University; Baltimore Maryland United States of America
5. Department of Oncology; School of Medicine; Johns Hopkins University; Baltimore Maryland United States of America