TP53 and breast cancer: We therefore first wanted to confirm these observations in the cell lines we use in the laboratory (human breast cancer (MCF7) and bone osteosarcoma (U2OS) cells) and also determine whether, as previously reported in A549 human lung carcinoma cells and U2OS cells, blocking both SSU and LSU pathways results in an additive effect on p53 induction (termed suprainduction; (45)).