SnapShot: Genetic Mouse Models of Cancer

p 53 T um o r S up p re ss o r Trp53 mouse germline knockout. Trp53−/− homozygous: 100% tumor penetrance at ?4.5 months. Typical tumors: T cell lymphoma (>60%); soft tissue sarcoma (?25%); osteosarcoma, brain tumors, teratoma (together <15%); carcinomas rarely observed. Trp53+/− heterozygous: 50% tumor penetrance at 17 months. Typical tumors: T cell lymphoma (?30%); soft tissue sarcoma (?30%); osteosarcoma (?30%); more carcinomas than Trp53−/− mice. Oncogenic cooperativity observed between Trp53−/− and other lesions such as Rb−/− or Eμ-Myc. Carcinogenesis induced by different genotoxic agents or irradiation is accelerated in Trp53-deficient mice. Mutations in TP53 found in more than 50% of all human tumors.