1. Division of Cancer Control and Population Sciences; University of Pittsburgh Cancer Institute; Pittsburgh PA
2. Department of Epidemiology; Graduate School of Public Health, University of Pittsburgh; Pittsburgh PA
3. Masonic Cancer Center, University of Minnesota; Minneapolis MN
4. Division of Epidemiology and Community Health; School of Public Health, University of Minnesota; Minneapolis MN
5. Department of Epidemiology; Shanghai Cancer Institute, Shanghai Jiaotong University; Shanghai China
6. Department of Biochemistry; Molecular Biology and BioPhysics, University of Minnesota; Minneapolis MN