title: Effects of age and parity on mammary gland lesions and progenitor cells in the FVB/N-RC mice.
abstract: The FVB/N mouse strain is extensively used in the development of animal models for breast cancer research. Recently it has been reported that the aging FVB/N mice develop spontaneous mammary lesions and tumors accompanied with abnormalities in the pituitary glands. These observations have a great impact on the mouse models of human breast cancer. We have developed a population of inbred FVB/N mice (designated FVB/N-RC) that have been genetically isolated for 20 years. To study the effects of age and parity on abnormalities of the mammary glands of FVB/N-RC mice, twenty-five nulliparous and multiparous (3-4 pregnancies) females were euthanized at 16-22 months of age. Examination of the mammary glands did not reveal macroscopic evidence of mammary gland tumors in either aged-nulliparous or multiparous FVB/N-RC mice (0/25). However, histological analysis of the mammary glands showed rare focal nodules of squamous changes in 2 of the aged multiparous mice. Mammary gland hyperplasia was detected in 8% and 71% of the aged-nulliparous and aged-multiparous mice, respectively. Epithelial contents and serum levels of triiodothyronine were significantly higher in the experimental groups than the 14-wk-old control mice. Immuno-histochemical staining of the pituitary gland pars distalis showed no difference in prolactin staining between the control and the aged mice. Tissue transplant and dilution studies showed no effect of age and/or parity on the ability of putative progenitor cells present among the injected mammary cells to repopulate a cleared fat pad and develop a full mammary gland outgrowth. This FVB/N-RC mouse substrain is suitable to develop mouse models for breast cancer.
authors.affiliation: Cell and Cancer Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Raafat
authors.forename: Luigi
authors.initials: L
authors.lastname: Strizzi
authors.forename: Karim
authors.initials: K
authors.lastname: Lashin
authors.forename: Erika
authors.initials: E
authors.lastname: Ginsburg
authors.forename: David
authors.initials: D
authors.lastname: McCurdy
authors.forename: David
authors.initials: D
authors.lastname: Salomon
authors.forename: Gilbert H
authors.initials: GH
authors.lastname: Smith
authors.forename: Daniel
authors.initials: D
authors.lastname: Medina
authors.forename: Robert
authors.initials: R
authors.lastname: Callahan
mesh_terms: D000375:Aging; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D008321:Mammary Glands, Animal / Q000473:pathology*; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D051379:Mice; D010053:Ovary / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D010298:Parity; D010902:Pituitary Gland / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D011980:Receptors, Progesterone / Q000378:metabolism; D013045:Species Specificity; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology*; D014599:Uterus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
chemical_list: D047628:Estrogen Receptor alpha; D011980:Receptors, Progesterone