High susceptibility of nullizygous p53 knockout mice to colorectal tumor induction by 1,2-dimethylhydrazine

Hiroki Sakai, Tetsuya Tsukamoto, Masami Yamamoto, Norimitsu Shirai, Takeshi Iidaka, Akihiro Hirata, Tokuma Yanai, Toshiaki Masegi, Lawrence A. Donehower, Masae Tatematsu

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Purpose: The susceptibility of male p53 nullizygote (-/-), heterozygote (+/-), and wild-type (+/+) mice to 1,2-dimethylhydrazine (DMH) induction of colon carcinogenesis was investigated. Methods: In a preliminary short-term experiment, male mice of three genotypes were given s.c. of 20 mg/kg DMH once weekly for 5 weeks. In a medium-term experiment, mice were given weekly s.c. of DMH for 15 weeks. In a long-term experiment, male p53 (+/-) and (+/+) mice were given weekly injections of DMH for 15 weeks, and killed at week 30. Results: In the medium-term experiment, carcinomas were observed in 70% of p53 (-/-) mice, although there were no carcinomas in p53 (+/+) and (+/-) mice. In the long-term experiment, there was no significant difference in incidences of adenomas and carcinomas between p53 (+/+) and (+/-) mice. PCR-single strand conformation polymorphism analysis of exons 5-8 of p53 gene revealed four mutations in one focal atypia, one adenoma, and two carcinomas, out of 56 colonic proliferative lesions in the medium- and long-term experiments. Conclusions: These results suggest that p53 might not be a direct target of DMH but complete loss of p53 might elevate susceptibility to DMH-induced colorectal carcinogenesis.

Original languageEnglish
Pages (from-to)335-340
Number of pages6
JournalJournal of Cancer Research and Clinical Oncology
Issue number6
Publication statusPublished - 01-06-2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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