1. Department of Clinical Cancer Prevention, Unit 1360, The University of Texas M. D. Anderson Cancer Center, Post Office Box 301439, Houston, TX 77230-1439, USA
2. Louisiana State University Health Science Center, New Orleans, LA, USA
3. Southwest Oncology Group Statistical Center, Seattle, WA, USA
4. Morehouse School of Medicine, Atlanta, GA, USA
5. Rush University Medical Center, Chicago, IL, USA
6. The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
7. National Cancer Institute, Bethesda, MD, USA
8. Ohio State University, Columbus, OH, USA
9. Cooperative Studies Program, Department of Veterans Affairs
10. University of Washington, Seattle, WA, USA