Impact of genetic background on spontaneous or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced intestinal tumorigenesis in Min/+ mice.

We have studied the impact of genetic background on susceptibility to spontaneous or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced intestinal tumorigenesis. The increase in small intestinal tumor number after PhIP exposure was 3.8- and 3.7-fold above the spontaneous levels in multiple intestinal neoplasia (Min)/+ F1 mice with AKR/J and A/J backgrounds, respectively, compared with only 3-fold in C57BL/6J mice. In the colon, PhIP increased the number of tumors slightly more in C57BL/6J mice (3.3-fold) than in A/J mice (3.0-fold). AKR/J mice had no colonic tumors. Most of the tumors were located in the distal two-thirds of the small intestine in all three strains.