- Strain differences of rats in the susceptibility to aberrant crypt foci formation by 2-amino-1-methyl-6-phenylimidazo- [4,5-b]pyridine: no implication of Apc and Pla2g2a genetic polymorphisms in differential susceptibility. Ishiguro, Y., Ochiai, M., Sugimura, T., Nagao, M., Nakagama, H. Carcinogenesis (1999)