TTK and histiocytoma: To evaluate the differential impact of MPS1 inhibition on the survival of cancer cells differing in their ploidy, we took advantage of a panel of diploid and tetraploid clones derived from parental human colon carcinoma HCT 116 and RKO cells, which we previously isolated and characterized [41], or from human malignant fibrous histiocytoma MFH152 cells, which we generated in this study by flow cytometry-assisted cloning [41].