Biomaterial Database

An evaluation of the hemizygous transgenic Tg.AC mouse for carcinogenicity testing of pharmaceuticals. I. Evidence for a confounding nonresponder phenotype. 1998

J L Weaver, and J F Contrera, and B A Rosenzweig, and K L Thompson, and P J Faustino, and J M Strong, and C D Ellison, and L W Anderson, and H R Prasanna, and P E Long-Bradley, and K K Lin, and J Zhang, and F D Sistare

Office of Testing and Research, Food and Drug Administration, Laurel, Maryland 20708, USA.

We have completed 2 26-wk studies to evaluate the hemizygous transgenic Tg.AC mouse, which has been proposed as an alternative short term model for testing carcinogenicity. We attempted to evaluate the response to the known rodent carcinogens cyclophosphamide, phenolphthalein, and tamoxifen and to the noncarcinogen chlorpheniramine following topical application. In the first study, a weak response (2/17 animals) was observed to the positive control 12-O-tetradecanoylphorbol 13-acetate (TPA in ethanol, 1.25 micrograms), and no response was observed to cyclophosphamide, phenolphthalein, or chlorpheniramine, despite evidence for skin penetration. The second study compared 1.25 micrograms and 6.25 micrograms of TPA in ethanol and acetone solutions. Tamoxifen was also evaluated in both solvents and orally. No significant response was observed to tamoxifen by skin paint or oral routes. Over 60% of the high dose TPA-treated animals showed no (0 or 1) papilloma response, and 30% of the animals each developed more than 32 papillomas. The heterogenous response to high dose TPA may be related to variability in the responsiveness of hemizygous animals. In light of these findings, further Tg.AC studies should employ homozygous animals, and the underlying cause for heterogeneity in the tumorigenic response of Tg.AC mice should be identified and eliminated.

UI	MeSH Term	Description	Entries
D008822	Mice, Transgenic	Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.	Transgenic Mice,Founder Mice, Transgenic,Mouse, Founder, Transgenic,Mouse, Transgenic,Mice, Transgenic Founder,Transgenic Founder Mice,Transgenic Mouse
D010212	Papilloma	A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)	Papilloma, Squamous Cell,Papillomatosis,Papillomas,Papillomas, Squamous Cell,Papillomatoses,Squamous Cell Papilloma,Squamous Cell Papillomas
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D002273	Carcinogens	Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.	Carcinogen,Oncogen,Oncogens,Tumor Initiator,Tumor Initiators,Tumor Promoter,Tumor Promoters,Initiator, Tumor,Initiators, Tumor,Promoter, Tumor,Promoters, Tumor
D000287	Administration, Topical	The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.	Drug Administration, Topical,Administration, Topical Drug,Topical Administration,Topical Drug Administration,Administrations, Topical,Administrations, Topical Drug,Drug Administrations, Topical,Topical Administrations,Topical Drug Administrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012878	Skin Neoplasms	Tumors or cancer of the SKIN.	Cancer of Skin,Skin Cancer,Cancer of the Skin,Neoplasms, Skin,Cancer, Skin,Cancers, Skin,Neoplasm, Skin,Skin Cancers,Skin Neoplasm
D015197	Carcinogenicity Tests	Tests to experimentally measure the tumor-producing/cancer cell-producing potency of an agent by administering the agent (e.g., benzanthracenes) and observing the quantity of tumors or the cell transformation developed over a given period of time. The carcinogenicity value is usually measured as milligrams of agent administered per tumor developed. Though this test differs from the DNA-repair and bacterial microsome MUTAGENICITY TESTS, researchers often attempt to correlate the finding of carcinogenicity values and mutagenicity values.	Tumorigenicity Tests,Carcinogen Tests,Carcinogenesis Tests,Carcinogenic Activity Tests,Carcinogenic Potency Tests,Carcinogen Test,Carcinogenesis Test,Carcinogenic Activity Test,Carcinogenic Potency Test,Carcinogenicity Test,Potency Test, Carcinogenic,Potency Tests, Carcinogenic,Test, Carcinogen,Test, Carcinogenesis,Test, Carcinogenic Activity,Test, Carcinogenic Potency,Test, Carcinogenicity,Test, Tumorigenicity,Tests, Carcinogen,Tests, Carcinogenesis,Tests, Carcinogenic Activity,Tests, Carcinogenic Potency,Tests, Carcinogenicity,Tests, Tumorigenicity,Tumorigenicity Test
D015430	Weight Gain	Increase in BODY WEIGHT over existing weight.	Gain, Weight,Gains, Weight,Weight Gains
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus