The production of cancer by pure hydrocarbons.—Part I

Abstract

Hydrocarbons are known to have the power to produce cancer in mice, for the carcinogenic mixtures obtained by heating acetylene or isoprene in an atmosphere of hydrogen (Kennaway, 1924, 1925) can consist only hydrocarbons. Moreover, the powerful fluorescenece of these and other carcinogenic mixtures (e. g., gas-works tar; shale oil; heated petroleum; products of the action of heat upon cholesterol, yeast, skin, muscle, and hair, and of the action of aluminium chloride upon tetralin) suggests that such hydrocarbons are of the polycyclic aromatic type. These mixtures gave a characteristic threebanded fluorescence spectrum, which resembled in character that of 1:2-benzanthracene. This significant observation led to the examination for carcinogenic action of a large number of pure polycyclic aromatic hydrocarbons of known molecular structure, particular attention being paid to compounds related to 1:2-benzanthracene (I). One such hydrocarbon, 1:2:5:6-dibenzanthracene (II), was prepared by the method of Clar (1929, a), and gave positive results. When the first four cancers produced in mice by this substances had been obtained, a preliminary account of the experiments was published (Hieger, 1930; Kennaway, 1930). We now have specimens of 102 cancers and 31 papillomas produced by this compound and its simple methyl derivatives, while various other compounds have given negative results. The production of tumours of subcutaneous tissue by injection of fatty media containing 1:2:5:6-dibenzanthracene has been recorded elsewhere (Burrows, Hieger and Kennawsy, 1932), and the numerous tumours of the peritoneal cavity which have been produced by similar methods are described by Burrows (1932).