Induction of oral mucosal tumors in hamsters and rats treated with methyl(acetoxymethyl)nitrosamine.

An oral tumor model has been developed in inbred Syrian golden hamsters by continuous applications every 2 weeks of methyl(acetoxymethyl)nitrosamine [(DMN-OAC) CAS: 56856-83-8; methylnitrosaminomethyl ester acetic acid] at 2 mg/kg body weight alone or by a single application of DMN-OAC followed by continuous twice weekly applications of 12-O-tetradecanoylphorbol 13-acetate (TPA) (1 microgram/animal). Similar studies were done in the W rat buccal mucosa. In the hamsters treated continuously with DMN-OAC, 100% of the tumors were observed in the cheek pouch; none were observed at other sites. In contrast, in the rats treated similarly, only a 67% tumor incidence was observed, of which only 42% were oral tumors. A promoter effect of TPA was observed in hamster cheek pouch tumors induced by DMN-OAC, whereas rat oral mucosa did not respond to TPA treatment.