[Esophageal tumor induction in monkeys].

The experiment used eight monkeys who had received such esophagotropic carcinogens as ethyl ester of N-nitrososarcosine and methyl-N-benzyl-N-nitrosamine. The animals were followed for 4 years. The former agent failed to induce cancer where as 3 monkeys who had received methyl-N-benzyl-N-nitrosamine in the total dose of 600, 625 and 720 mg developed esophageal tumors (papilloma-2 and squamous cell carcinoma-1) at days 527, 725 and 880 after the start of treatment. The biological and histological features of the tumors were close to those of their human counterparts.