MAMBNA is a new N-nitroso compound isolated from Fusarium moniliforme-inoculated corn meal. In the present studies the carcinogenicity of
MAMBNA is shown by the induction of forestomach
carcinomas and liver
tumors in mice and rats following the gastric intubation of this compound. Among 42 mice of Kunming (KM) stock treated with
MAMBNA (10-20 mg/week), 22 showed epithelial
hyperplasia of the esophagus, 29
papillomas and 4
squamous carcinomas in the forestomach, and there were 6 liver
adenomas and 3
hepatomas. One mouse had forestomach
carcinoma and
carcinoma in the liver. Most
tumors developed in mice receiving the treatment for 136-317 days, with a total dose of 210-670 mg (Table 1). No
tumor was found in 12 controls observed for 239-357 days. In the experiment with 29 Wistar strain rats, administration of
MAMBNA (20-120 mg/week) resulted in 11 epithelial
hyperplasias in the lower esophagus, 14 atypical
hyperplasias and
papillomas, and 11
squamous carcinomas in the forestomach. The earliest forestomach
carcinoma appeared in a rat treated for 454 days, receiving 4480 mg of
MAMBNA, and the other 10
carcinomas occurred in animals treated for 518-640 days.
Hyperplasia of liver cells was noted in 4 rats and liver
adenoma in 7 and
hepatocellular carcinoma in 8. Most
hepatomas developed in rats treated for 480-640 days, and 5 rats had both forestomach
carcinoma and
hepatoma (Table 2). In 11 untreated rats observed for 411-644 days only one forestomach
papilloma was noted.