Mutations in tumor suppressor genes (APC, DCC, Smad-2, Smad-4, p53) and oncogenes (K-ras) are molecular determinants occurring during the development of sporadic colorectal cancer, which was first summarized in the adenoma-carcinoma sequence described by Vogelstein et al. [5-7]. The gene discussed is TP53; the disease is colorectal cancer.