To test the activity of DAT1 in cell lines where the action of p53 is suppressed, we have used colon cancer cell lines HT29, SW620 and SW480 with mutated p53 [38] and HCT116 p53−/−, an isogenic p53 knock out (p53 −/−) line and compared with p53 wild type cell line HCT116 (p53 +/+). The gene discussed is TP53; the disease is malignant colon neoplasm.