The target organ table reports results on chemicals in the CPDB that induce tumors in each of 35 target organs in rats, mice, hamsters, monkeys, or dogs. The table is organized alphabetically by target site and within each site, by species and chemical. The total number of positive chemicals in the CPDB for each species is 564 for rats, 442 for mice, 44 for hamsters, 11 for monkeys, 3 for dogs and 1 each for bush babies and tree shrews.

A chemical is listed under each target organ that has been evaluated by at least one published author as a target site in at least one experiment in rats, mice, hamsters, monkeys, dogs or prosimians. Since many chemicals induced tumors at multiple sites, a chemical may be listed under several target organs. Every chemical listed in the table is positive in at least one species. In order to compare results in rats and mice, symbols follow chemicals that have been tested in both these species.

Purposes of this target organ compendium are:

• For many research issues in carcinogenesis it is valuable to have quick access to a list of chemicals that have been found in chronic bioassays to induce tumors at each target site in various species.
• Comparison of target sites in several species is possible for work on interspecies extrapolation. Investigations of chemical structure or mechanism of carcinogenesis at a specific target site can identify chemicals that induce tumors in that organ.
• Comparative toxicological analyses are facilitated by indicating in the table whether a chemical that is positive at a given site in the rat has been tested in the mouse, whether results are also positive in the mouse, and whether the target organs are the same in the two species. By cross-referencing a chemical of interest to the published plots of the CPDB, details of each experiment can be obtained.

Example of Adrenal gland, which is the first of 35 target sites in the table.

Under adrenal gland, one chemical is listed in hamsters, 8 in mice, and 18 in rats. If a chemical name is followed by a superscript (either ^† or ^‡), this indicates that the CPDB includes test results in both rats and mice, e.g., under adrenal gland in rats 2-mercaptobenzothiazole but not isomazole, has a superscript. Since isomazole has no superscript, it only has tests in the CPDB in the species reported, in this case rats. The superscript ^† for 2-mercaptobenzothiazole, indicates that the chemical has been tested in both rats and mice but induced tumors only in the reported species, in this case rats. The superscript ^‡; for 1,2-dibromo-3-chloropropane (DBCP) indicates that DBCP is carcinogenic at some target site in both rats and mice. Although the superscript ^‡; does not indicate whether DBCP induced tumors at the same target site in both rats and mice, this can easily be determined by looking at mice under adrenal gland for the chemical name DBCP. Since DBCP is not listed under mice, it induced tumors in mice only at sites other than the adrenal gland. In contrast, pentachloroanisole^‡; induced adrenal tumors in both species, since it is listed under that site for both species. By comparing the chemicals with superscripts listed under each species, the reader can determine that pentachloroanisole is the only chemical that induced adrenal tumors in both rats and mice. The superscripts ^† and ^‡; apply only to results in rats and mice: for example, hamsters are reported under adrenal gland for urethane with the symbol ^‡; indicating that urethane was positive at some site in rats and mice; however, the superscript does not indicate anything about hamsters.

View the current target organ table.

Since rats and mice are the usual species tested, we provide a frequency table of target sites for these species, based on the results presented in the compendium. This summary table permits simple comparisons of target site prevalence between species and between mutagens and nonmutagens. In the frequency table, the target sites are ordered by how often the site is positive in rats or in mice. A summary of the compendium is given under the headings “All Chemicals” for rats (N=564) and mice (N=442).

Additionally, for the subset of carcinogens that have been evaluated in Salmonella (N=502), the frequency of target sites in each species is reported separately for mutagens and nonmutagens. A chemical is classified as mutagenic in the Salmonella assay if it was evaluated as either “mutagenic” or “weakly mutagenic” by Zeiger (1997) or as “positive” by the Gene-Tox Program (Kier et al., Auletta, USNLM). All other chemicals that have been evaluated by these sources are reported as nonmutagens in the frequency table. Of the 1547 chemicals in the CPDB, 860 have evaluations of mutagenicity in Salmonella from these sources.

Target organs in humans are also summarized in Table 3 of Gold et al. (2001) for 82 agents that were evaluated at that time by the International Agency for Research on Cancer (IARC) as carcinogenic to humans at some target site. The table indicates whether any target sites in laboratory animals were reported in the CPDB at that time.

1. Gold, L.S., Manley, N.B., Slone, T.H., and Ward, J.M. (2001). Compendium of chemical carcinogens by target organ: Results of chronic bioassays in rats, mice, hamsters, dogs and monkeys. Toxicol. Pathol. 29: 639-652. PDF
2. (Gold L.S., Zeiger E., eds. (1997). Genotoxicity Database. In: Handbook of Carcinogenic Potency and Genotoxicity Databases CRC Press, Boca Raton, FL, pp. 687-729.
3. Kier, L. E., Brusick, D. J., Auletta, A. E., Von Halle, E. S., Brown, M. M., Simmon, V. F., Dunkel, V., McCann, J., Mortelmans, K., Prival, M., Rao, T. K., Ray, V. (1986). The Salmonella typhimurium/mammalian microsomal assay: A report of the U.S. Environmental Protection Agency Gene-Tox Program. Mutat. Res. 168:69-240.
4. Auletta, A. E. pers. comm.
5. U.S. National Library of Medicine (2001). Gene-Tox Database.

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Last updated: August 6, 2007