1. Pancreatic Tumor Study Group, Department of Surgical Oncology, Box 106, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77 030, USA
2. Department of Diagnostic Radiology, Box 106, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77 030, USA
3. Department of Pathology, Box 106, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77 030, USA