- Oral administration of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) yields PhIP-DNA adducts but not tumors in male Syrian hamsters congenic at the N-acetyltransferase 2 (NAT2) locus. Fretland, A.J., Devanaboyina, U.S., Feng, Y., Leff, M.A., Xiao, G.H., Webb, S.J., Hein, D.W. Toxicol. Sci. (2001)