Induction of Adenocarcinomas in the Glandular Stomach of BALB/c Mice Treated with N‐Methyl‐N‐nitrosourea

Male 6‐week‐old BALB/c strain animals (groups 1 and 2) received 10 weekly intragastric intubations of 0.5 mg/mouse of N‐methyl‐N‐nitrosourea. At week 11 the forestomachs were resected in group 1 but not group 2. Although many animals in group 2 died due to development of squamous cell carcinomas in the forestomach, development of cancers in the glandular stomach was quite similar in both groups. Well‐differentiated adenocarcinomas in groups 1 and 2 were found at low incidence at week 20, rising to 100% at week 40, with two lesions metastasizing to the lymph nodes. Four poorly differentiated adenocarcinomas and 5 signet ring cell carcinomas were also found in 27 glandular stomach tumor‐bearing animals.