Induction of an Immunological Response in Local Lymph Nodes by Chemical Carcinogens

Abstract

AFTER a period during which intensive investigation of carcinogenesis continued along classical lines, there has recently developed a major shift in emphasis as it is becoming more apparent that certain carcinogens, even when applied locally, are capable of initiating significant changes in the genetic apparatus of the host cells. Some of the present developments have, to a large extent, been the outgrowth of investigations showing that some carcinogens arrest the synthesis of DNA dependent RNA, in a manner similar to actinomycin-D. Structurally related non-carcinogens, on the other hand, exert no such action. These results indicate the possibility that the initial event in carcinogenesis might be an impairment in the expression of genetic (DNA dependent RNA) information, as has been suggested recently by De Maeyer and De Maeyer-Guignard¹. Gelboin and Klein² have, moreover, shown that tumour formation by 7,12-dimethyl-benz(a)anthracene can be markedly inhibited by the topical application of actinomycin-D before and after treatment. This would also support classical models for carcinogenesis such as that suggested by the work of Monod and Jacob on genetic systems in micro-organisms³.