Dr. Guan Chen previously worked in Sun Yat-sen University and German cancer research Center as well in Dana-Farber focused on investigating on biochemical mechanisms involved in cancer drug response by discovering Thaliblastine as a novel and non-toxic p-glycoprotein inhibitor to reverse multiple drug resistance (Cancer Res 1993;53:2544-7,) and nonpolyglutamatable antifolates as new analogues to reverse the resistance (Mol Pharmacol 1995;48:758-65).