1. Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
2. Laboratory of Cancer Prevention, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
3. Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany
4. SAIC-Frederick, NCI-Frederick, Frederick, Maryland 21702, United States