1. Department of Surgery and Comprehensive Cancer Center, The University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, Instrumental Analysis and Bioanalysis, Saarland University, 66123 Saarbrucken, Germany, and Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201