Mice, Inbred AKRMice, Mutant StrainsNeoplasm TransplantationMammary Neoplasms, ExperimentalDisease Models, AnimalMice, TransgenicPhenotypeMice, Inbred C57BLMutationAKR murine leukemia virusHydroxyprostaglandin Dehydrogenases20-Hydroxysteroid DehydrogenasesAldehyde Reductase3-Hydroxysteroid DehydrogenasesLeukemia Virus, MurineLeukemia, ExperimentalKetosteroidsHydroxysteroid Dehydrogenases3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)Alcohol OxidoreductasesThymus Neoplasms