CK attenuated the HK-1 tumor growth in vivo . (A) Chemical structure of ginsenoside-CK. (B) The HK-1 xenograft tumor model was established by injecting 3 × 106 cells subcutaneously to the left and right flanks of nude mice, respectively. Animals (4 mice per group) were treated with 10 mg/kg/day CK or 0.5% CMC (as control) orally for 5 days when tumors were palpable. Tumor sizes were measured daily. **P < 0.01 and ***P < 0.001 compared to the control group.