Yong Li1, Hua Lu2. 1. Department of Biochemistry and Molecular Biology, School of Medicine, University of Louisville, 319 Abraham Flexner Way, Louisville, KY 40202, USA. 2. Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA E-mail: hlu2@tulane.edu.