The fifth plot of the carcinogenic potency database: Results of animal bioassays published in the general literature through 1988 and by the national toxicology program through 1989

Abstract

This paper is the fifth plot of the Carcinogenic Potency Database (CPDB) that first appeared in this journal in 1984. We report here results of carcinogenesis bioassays published in the general literature between January 1987 and December 1988, and in technical reports of the National Toxicology Program between July 1987 and December 1989. This supplement includes results of 412 long-term, chronic experiments of 147 test compounds and reports the same information about each experiment in the same plot format as the earlier papers: the species and strain of test animal, the route and duration of compound administration, dose level and other aspects of experimental protocol, histopathology and tumor incidence, TD50 (carcinogenic potency) and its statistical significance, dose response, author's opinion about carcinogenicity, and literature citation. We refer the reader to the 1984 publications for a guide to the plot of the database, a complete description of the numerical index of carcinogenic potency, and a discussion of the sources of data, the rationale for the inclusion of particular experiments and particular target sites, and the conventions adopted in summarizing the literature. The five plots of the database are to be used together, as results of individual experiments that were published earlier are not repeated. In all, the five plots include results of 4487 experiments on 1136 chemicals. Several analyses based on the CPDB that were published earlier are described briefly, and updated results based on all five plots are given for the following earlier analyses: the most potent TD50 value by species, reproducibility of bioassay results, positivity rates, and prediction between species. A new feature of this supplement is that Appendix 14 now provides a summary compendium of positivity and potency, as well as an index to all chemicals in the five plots of the CPDB. It provides the following summary data for each chemical: (a) whether it has been tested in each sex of rats and mice, and positivity results in each group; (b) for positive chemicals, a summary of carcinogenic potency for rats and for mice; (c) an index to the CPDB sorted by chemical name that reports synonyms, CAS number, and the plot numbers that include experiments on the chemical. For readers using the CPDB more extensively, a combined plot of all results from the five separate plot papers, ordered alphabetically by chemical is available from the first author in printed form or on computer tape or diskette. A SAS database is also available.