Induction of preneoplastic nodules: quantitative predictivity of carcinogenicity.

Using data from two independent studies, the quantitative predicitivity of carcinogenicity of the liver preneoplastic nodules test was examined. It was compared with the predicitivity of two short-term parameters: the Ames test and acute toxicity. In analyzing the results of both studies, a rather high quantitative predictivity was shown for the preneoplastic nodules (r = 0.43 and r = 0.60, respectively). For one study, the predictivity was approximately of the same order as the internal consistency of the carcinogenicity data (median r = 0.69). The preneoplastic nodules were more predictive than the Ames' test as a statistical trend. The predictivity of the Ames' test has been found to be rather poor; especially in one case where r = 0.10. As expected, acute toxicity was the less predictive short-term parameter.