Chemicals organ-specific carcinogenicity

Certain chemicals clearly show organ-specific carcinogenicity. For instance, butylhydroxybutylnitrosamine produces bladder cancer very specifically in rats and mice.However, S-9 from rat kidney was less active than that from rat liver, and S-9 from rat bladder had only weak activity. Methylbenzylnitrosamine, which specifically induces esophageal cancer in rats and dogs, was effectively activated by rat liver Thus, S-9 from the liver... 

One of the more important classes of chemical carcinogens are N-nitrosamines. They are important because practically all of the simple nitrosamines are carcinogenic, they are widely distributed in our environment and can be formed in the stomach from secondary and tertiary amines and the ubiquitous nitrite ion. Moreover, nitrosamines are very organ-specific. Thus, a given nitrosamine will produce a liver or an esophageal tumor, regardless of the route of administration of the carcinogen. This fact makes nitrosamines very useful in the study of mechanisms of tumor induction (1). 

Likewise, one can speculate that organ-specific enzymes or enzyme concentrations can be involved in the activation of carcinogens and, therefore, in the induction of organ-specific cancers, so-called organotropism. In such cases, the use of a postmitochondrial fraction from liver homogenate cannot be expected to activate these chemicals as occurs extrahepatically. 

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