1. The Jim Ayers Institute for Precancer Detection and Diagnosis, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, and Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232