In this report, tumor phenotypes were examined using mice carrying Apc, Kras, and Trp53 (AKP) mutations, and metastasis was found in about 7–8% of both Trp53null and Trp53R270H/LOH mice, suggesting the need for additional genetic alterations in order to induce metastasis formation. The gene discussed is KRAS; the disease is neoplasm.