TP53 and urinary bladder carcinoma: To investigate the ability of the synthetic aptazyme to discriminate p53 wild-type cells and p53 mutant cells, luciferase assays were performed in four cell lines, including HCT116 p53-/- (human colon cancer cells with p53 knockout), 5637 (bladder cancer cells), SCL-1 (cutaneous squamous cell carcinoma cells) and G361 (human melanoma cells).