We first tracked cell proliferation in a human colon cancer cell line HCT116 (wild type p53), a human non-small cell lung carcinoma cell line H1299 (p53 null) and a human cervical cancer cell line HeLa (p53 inactivated by E6) (from the IARC TP53 Database, URL: http://www-p53.iarc.fr). The gene discussed is TP53; the disease is malignant colon neoplasm.