Pulmonary carcinogenesis by derivatives of polynuclear aromatic alkylating agents

Simple alkylating derivatives of polycyclic aromatic hydrocarbons have been found to be much more carcinogenic in the Strain A mouse than are the parent hydrocarbons. It has also been shown that the carcinogenicity of these halomethyl hydrocarbons is not a function of the first-order solvolysis rate. The acridine antitumor agent and mutagen ICR 170, 2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]acridine dihydrochloride, has been shown to be a potent carcinogen in the same system when administered i.v., superseding data in the literature indicating inactivity when the drug is administered i.p. Stimulation of the immune system has been shown to have a marked inhibitory effect on the carcinogenic activity of this compound.