1. Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts.
2. Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts.
3. Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts.
4. Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
5. Departments of Surgery and Anesthesia, Boston Children's Hospital, Boston, Massachusetts.
6. Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.