title: Transgenic Polyoma middle-T mice model premalignant mammary disease.
abstract: Mice transgenic for the Polyomavirus middle T (PyV-mT) gene have been widely used to study mammary tumorigenesis and metastasis. Although numerous molecular insights were gained from the analysis of these transgenic malignant tumors, the early events leading to malignant transformation have not been systematically investigated nor has the biological potential of hyperplastic lesions been documented. This paper presents the first comprehensive histopathological characterization of transgenic PyV-mT hyperplasias together with classical transplantation experiments designed to test the growth potential of these lesions. Moreover, stable hyperplastic outgrowth lines were established as a tool to study premalignant PyV-mT-induced hyperplasias in detail. Each line has a different tumor latency, indicating that PyV-mT-induced hyperplasias, like early proliferative lesions seen in the human breast, are heterogeneous with respect to their malignant potential. Our results settle a controversy; they establish that PyV-mT gene expression alone is insufficient to induce tumors and that additional events are required for tumorigenesis and metastasis. These results support the use of PyV-mT transgenic mice as a model for investigating the multistep progression of malignant mammary tumorigenesis and metastasis.
authors.affiliation: Department of Medicine, Cancer Center, School of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Maglione
authors.forename: D
authors.initials: D
authors.lastname: Moghanaki
authors.forename: L J
authors.initials: LJ
authors.lastname: Young
authors.forename: C K
authors.initials: CK
authors.lastname: Manner
authors.forename: L G
authors.initials: LG
authors.lastname: Ellies
authors.forename: S O
authors.initials: SO
authors.lastname: Joseph
authors.forename: B
authors.initials: B
authors.lastname: Nicholson
authors.forename: R D
authors.initials: RD
authors.lastname: Cardiff
authors.forename: C L
authors.initials: CL
authors.lastname: MacLeod
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000096:biosynthesis / Q000235:genetics*; D002455:Cell Division / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D015870:Gene Expression; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009368:Neoplasm Transplantation; D011230:Precancerous Conditions / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D011960:Receptors, Estrogen / Q000096:biosynthesis; D011980:Receptors, Progesterone / Q000096:biosynthesis; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
chemical_list: D000952:Antigens, Polyomavirus Transforming; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D016159:Tumor Suppressor Protein p53