Based on the 56 mice we observed (45 p53+/− and 11 p53−/−), four p53+/− mice (8.9%) developed sarcomas between 3 to 11 months, while nine p53−/− (81.8%) developed lymphoma and sarcomas at age 9 to 12 weeks before succumbing to their disease. This evidence concerns the gene TP53 and lymphoma.