Data selection and treatment of chemicals tested for genotoxicity and carcinogenicity.

A database containing qualitative and quantitative results of experimental studies in the fields of genotoxicity and carcinogenicity has been developed. By analyzing results of the studies performed by the U.S. National Toxicology Program, or by a similar program developed in Japan, or reported in the scientific literature, as well performed by private organizations, information has been collected relating to 3389 chemicals, identified by their CAS number. The studies considered for the database include three genotoxicity/mutagenicity short-term test (STTs), namely, two in vitro (Salmonella, gene mutation assay, and mammalian cells/human lymphocytes chromosome aberration assay) and one in vivo, the rodent bone marrow micronucleus assay. To investigate the possible predictive value of these STT assays for carcinogenicity, the results of animal long-term bioassays have also been collected. We have re-evaluated all the genotoxicity studies and the majority of those cases studied in different laboratories with contrasting results has been resolved; a small proportion of questionable cases is, however, still present in the database. In total, 2898 (85.5%) of the chemicals have been tested in the Salmonella assay; 1399 (41.3%) have been tested in the in vitro chromosome aberration assay; 319 (9.4%) have been tested in the in vivo rodent bone marrow cell micronucleus assay; 716 (21.2%) of the chemicals have been tested in the in vivo animal long-term bioassay. For 1118 chemicals tested in the Salmonella assay, 30,650 quantitative studies have been included in the database, thus allowing a possible classification of mutagenic chemicals according to their mutagenic potency.(ABSTRACT TRUNCATED AT 250 WORDS)