Differential sensitivity to lung tumorigenesis following transplacental exposure of mice to polycyclic hydrocarbons, heterocyclic amines, and lung tumor promoters

Research conducted by this laboratory over the past decade has demonstrated the high susceptibility of the fetus to lung tumor formation following in utero exposure of the resistant C57BL/6 and DBA/2N strains of mice to 3-methylcholanthrene (MC). In this review, we describe our more recent studies on the effects of MC and cotreatment with the lung tumor promoter, butylated hydroxytoluene (BHT), on lung tumor formation in the intermediately susceptible BALB/c strain of mice, and the determination of the potential carcinogenicity of the heterocyclic amine, 2-amino3-methylimidazo[4,5-f]quinoline (IQ) in resistant mouse strains. BALB/c mice showed a similar incidence of lung tumors, both in terms of percentage of mice with tumors and number of tumors per mouse, as found in the resistant [D2 B6D2F1]F2 mice. Ki-ras point mutations were found in 56% (20/36) of BALB/c lung lesions compared with an incidence of 79% in [D2 B6D2F1]F2 mice. BALB/clung lesions demonstrated a similar association of Ki-ras