VALIDATION OF THE SOS UMU TEST USING TEST-RESULTS OF 486 CHEMICALS AND COMPARISON WITH THE AMES TEST AND CARCINOGENICITY DATA/

The present study gives a comprehensive update of all umu genotoxicity assay results published so far. The available data of 486 chemicals i nvestigated with the umu test are compared with the Ames test (274 com pounds) as well as rodent carcinogenicity data (179 compounds). On the whole, there is good agreement between the umu test and the Ames test results, with a concordance of about 90%. The umu test was able to de tect 86% of the Ames mutagens, while the Ames test (using at least 5 s trains) detected 97% of the umu positive compounds. The elimination of TA102 from the set of Ames tester strains reduced the percentage of d etectable umu genotoxins from 97 to 86%. The agreement between carcino genesis and umu response was 65%, which is comparable to earlier studi es concerning rodent carcinogenesis and Salmonella mutagenesis. The pr esent compilation of umu results provides a database that can be used for the comparison of the SOS-inducing activity of chemicals and their mutagenicity, respectively, carcinogenicity. The results presented he re clearly demonstrate that a chemical which induces the expression of the umu operon can be regarded a rodent carcinogen with a high degree of certainty (93%).