Induction of gastric cancer in monkeys by N-methyl-N-nitro-N-nitrosoguanidine (MNNG).

N-methyl-N-nitro-N-nitrosoguanidine (MNNG) was administered to 9 Macaca fascicularis monkeys (7 males and 2 females) through a tube at a dose of 40 mg/kg body weight 3 times a month. Tumors of the pyloric part of the stomach were observed in 2 male monkeys after MNNG doses of 800 and 848 mg/kg body weight, with a latent period of tumor development of 49 and 50 weeks, respectively. Histologically, in one case the tumor was a solid carcinoma, and in the other it had a mixed structure showing alternating solid and signet ring cell carcinoma areas.