Induction of colon cancer in inbred Syrian hamsters by intrarectal administration of benzo[alpha]pyrene, 3-methylcholanthrene and N-methyl-N-nitrosourea.

Large bowel neoplasms were induced in male Syrian hamsters of the inbred strain BIO15.16 by intrarectal instillation of benzo[alpha]pyrene (BP), 3-methylcholanthrene (3-MC) or N-methyl-N-nitrosourea (MNU). Groups of hamsters were given 0.8 mg BP once weekly for 30 weeks, 0.8 mg 3-MC twice weekly for 30 weeks, or 0.8 mg MNU once weekly for 15 weeks. The experiment was terminated after 1 year. The incidences of colon neoplasms were 6% with BP exposure, 20% with 3-MC and 95% with MNU. The colon neoplasms induced by BP and 3-MC were mostly adenocarcinomas. In the group given MNU, adenocarcinomas were also produced but a substantial incidence of squamous cell carcinomas was found. These results demonstrate that the colonic mucosa of this strain of hamster is quite susceptible to cancer induction.