CKS1B and fibrosarcoma: The cytotoxicity of CKS1 was not limited to 4T1 cells, and CKS1 was found to be effective in several murine and human cancer cell lines: CT26 murine colon carcinoma cells with an IC50 of 53 μM ± 9.9 μM (Fig. 2C), human osteosarcoma U2OS cells, and murine fibrosarcoma MCA205 cells (Fig. S1A, B).