SENCAR Mouse Skin Papillomas Induced by 6-Methylbenzo[a]pyrene Carry H-ras Codon 52 (CTALeu → CCAPro) and Codon 13 (GGCGly → GTCVal) Mutations

Organic smoke contains various methylated polycyclic aromatic hydrocarbon (PAH) carcinogens. Among these, 6-methylbenzo[a]pyrene (6-CH3BP) is a moderate carcinogen. In vitro, it can form both stable and depurinating adducts. Of these, only two depurinating adducts [BP-6-CH2-N7G and 6-CH2BP-(1&3)-N7G] have been detected in mouse skin. We examined seven 6-CH3BP-induced SENCAR mouse skin papillomas for the presence of oncogenic H-ras mutations. Two papillomas contained the codon 52 (CTALeu → CCAPro) and a third contained the codon 13 (GGCGly → GTCVal) mutation. These results suggest that the H-ras codon 52 mutation is an oncogenic mutation.