In vivo efficacy of CKI in the MCF-7 SP xenograft model. (A) Tumor volumes (Mean ± SEM) were plotted for each group (n = 6 per group). Both CKI and DDP suppressed tumor growth. (B) A representative comparison image of the incised tumors from CKI, DDP, and the control group. (C) The tumor formation rate of the control group was 100% (6/6), while that of CKI group was 33.33% (2/6) and that of the DDP group was 50% (3/6) (* P < 0.05). (D) A representative mouse specimen without a tumor from the CKI group. (E) A representative specimen with a tumor from the control group. (F) Schematic outline of mice body weight (mean ± SD). No body weight loss was observed in the CKI group, but a slight body weight loss was observed in the DDP group compared to the control group.