1. Department of Medicine and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
2. Epithelial Biology Program, Department of Surgery and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
3. Department of Gastrointestinal Surgery, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan.
4. Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
5. The Veterans Administration Medical Center, Nashville, TN 37232, USA.