RB1 and malignant colon neoplasm: However, AZD2811-treatment of RB+p53 wild type HCT116 colon cancer cells, HT1080 fibrosarcoma cells and normal neonatal foreskin fibroblasts showed accumulation of cells with >4n DNA content which should not be possible if the p53-dependent tetraploidy checkpoint functioned as modelled (Figs. 2A and S3A).