Does carcinogenic potency correlate with mutagenic potency in the Ames assay?

Abstract

AN approximately linear relationship between the mutagenic potency of a chemical in the Salmonella reverse mutation assay of Ames1 and its carcinogenic potency in animals, was recently alluded to2 and has since been discussed at several international symposia3,4. The implications of such a claim are clearly momentous. At present, the fact that the Salmonella assay can give both false positive and false negative results when compared with animal tests6,7 has led to its being regarded as an early warning system rather than the final arbiter of animal and possibly human carcinogenicity. A correlation between mutagenic and carcinogenic potency would, however, mean that a strong positive response in the Ames assay would define a potentially potent carcinogen, and would suggest that some compounds give positive results in this assay but fail to induce cancer in animals because their mutagenic potency is too low. We believe, however, that there is sufficient experimental evidence to treat any superficial potency correlation with great caution at this stage.