o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea, which are mutagenic but not carcinogenic in the colon, rapidly induce colonic tumors in mice with dextran sulfate sodium-induced colitis

Table 1 Incidence of colonic dysplastic foci and tumors induced by a CMNC in combination with DSS

Treatment	Dysplasia	Adenoma	Adenocarcinoma	Tumor^a
Non-treatment	0% (0/8)	0% (0/8)	0% (0/8)	0% (0/8)
Vehicle^b + 4% DSS	0% (0/13)	0% (0/13)	0% (0/13)	0% (0/13)
AAT (125 mg/kg/day)	0% (0/6)	0% (0/6)	0% (0/6)	0% (0/6)
AAT (125 mg/kg/day) + 4% DSS	75% (6/8)***	100% (8/8)***	100% (8/8)***	100% (8/8)***
DMBA (25 mg/kg/day)	0% (0/5)	0% (0/5)	0% (0/5)	0% (0/5)
DMBA (25 mg/kg/day) + 4% DSS	50% (3/6)**	50% (3/6)**	50% (3/6)**	83% (5/6)***
ENU (11 mg/kg/day)	0% (0/6)	0% (0/6)	0% (0/6)	0% (0/6)
ENU (11 mg/kg/day) + 4% DSS	100% (7/7)***	100% (7/7)***	100% (7/7)***	100% (7/7)***

The numbers in parentheses indicate the number of mice with dysplasias, adenomas, or adenocarcinomas per the number of mice
CMNC; colon-mutagenic non-carcinogen
^a: adenoma + adenocarcinoma
^b: water for injection for 7 mice and salad oil for 6 mice
^{**, ***}; significantly different from the DSS alone group at P < 0.05, 0.01 in Fisher’s exact probability test

ISSN: 1880-7062