Induction of gastric carcinomas in nonhuman primates by N-ethyl-N'-nitro-N-nitrosoguanidine.

N-Ethyl-N'-nitro-N-nitrosoguanidine [(ENNG) CAS: 63885-23-4] was administered to 5 Macaca monkeys (Macaca mulatta and M. irus) at a concentration of 200 or 300 micrograms/ml for 11-26 months in their drinking water. Gastric carcinomas in the pyloric region were observed in all 5 monkeys between experimental months 11 and 38. Histologically, these carcinomas were mainly poorly differentiated adenocarcinomas and signet-ring cell carcinomas, and a few moderately and well-differentiated adenocarcinomas were also found. The macroscopic and histologic appearances of these carcinomas were similar to those in humans.