Time-dependent reduction in animal body weight, tumor volume, and tumor weight in RD-ES xenografts following treatments. Treatments for 15 days: control (CTL), 4-HPR (20 μg/kg/day), GST (2 mg/kg/day), and 4-HPR (20 μg/kg/day) plus 4-h later GST (2 mg/kg/day). (A) Body weight changes; (B) tumor volume changes; and (C) tumor weight changes after therapies. Combination therapy showed best efficacy in reducing animal body weight and tumor volume. We used 6 animals per group (*P < 0.05 or **P < 0.001).