Mammary tumorigenesis in genetic crosses between the high mammary tumor incidence GR and the low incidence C57BL mouse strains is highly correlated with murine mammary tumor virus expression in milk. Although the F1 and first backcross females had a mammary tumor incidence which was consistent with a single dominant gene segregation, the tumor incidence in the critical second backcross segregan...

Tissue inhibitor of metalloproteinases-1 (TIMP-1) regulates matrix metalloproteinase activity, acts as a growth stimulator and inhibits apoptosis. We developed transgenic mice to evaluate the relevance of circulating versus mammary TIMP-1 in mammary carcinogenesis. The transgene was placed under the control of the albumin (Alb) promoter for the production of large amounts of TIMP-1 in the liver...

Cks1 plays an essential role in SCFSkp2-mediated ubiquitination, and consequently turnover, of the cdk2 inhibitor and tumor supressor p27Kip1. High Cks1 expression is associated with aggressive breast tumors and correlates with low p27Kip1 levels in some cases, although it is also an independent prognostic marker for survival, and provides predictive information in addition to that provided by ...

Rats treated with the alkylating agent methylnitrosourea (MNU) develop multiple, hormonally dependent mammary tumors. Roughly 50% of the tumors have Ha-ras mutation, whereas 50% do not. The MNU-induced rat mammary tumor model was employed to examine the therapeutic efficacy of the farnesyltransferase inhibitor (FTI), R115777, and to examine the use of genomics in identifying susceptible tumors ...

BACKGROUND MMTV-Wnt1 transgenic mice develop mammary hyperplasia early in development, followed by the appearance of solitary mammary tumors with a high proportion of cells expressing early lineage markers and many myoepithelial cells. The occurrence of tumors is accelerated in experiments that activate FGF proto-oncogenes or remove the tumor suppressor genes Pten or P53, implying that secondar...

We concentrated ourselves to evaluate the prognostic significance of the p53 gene mutations, its protein expression and MIB-1 index as a proliferative marker in canine mammary tumors. In the present study, a total of 20 cases were examined, among which there were 5 malignant mixed tumors, 4 mammary gland adenocarcinomas, 1 papillary adenocarcinoma, 8 benign mixed tumors and 2 mammary gland aden...

Prolactin (PRL) is a key player in the development of mammary cancer. We studied the effects of parity or hyperprolactinemia on mammary carcinogenesis in OFA hr/hr treated with 7,12-dimethylbenzanthracene. They were divided into three groups: nulliparous (Null), primiparous (PL, after pregnancy and lactation), and hyperprolactinemic rats (I, implanted in the arcuate nucleus with 17β-estradiol)....

The tyrosine kinase receptor Ron has been implicated in several types of cancer, including overexpression in human breast cancer. This is the first report describing the effect of Ron signaling on tumorigenesis and metastasis in a mouse model of breast cancer. Mice with a targeted deletion of the Ron tyrosine kinase signaling domain (TK / ) were crossed to mice expressing the polyoma virus midd...

Iron body-stores and iron dietary intake have been sporadically reported to increase the risk of cancer in humans. To investigate the effect of iron on the development of mammary tumors, female Sprague-Dawley rats were given dimethylbenz[a]anthracene (DMBA) (5 mg/kg, i.g., 1x) at 55 days of age. Eight days later, rats received iron(II) sulfate s.c. (50 micromol/kg, 2x/week) for 53 weeks. Mammar...

Cyclin E activates Cdk2, controls centrosome duplication, and regulates histone gene transcription. Cyclin E is deregulated in cancer and appears as low-molecular-weight (LMW) isoforms that correlate strongly with decreased survival in breast cancer patients. Transgenic mice overexpressing LMW-cyclin E have increased incidence of mammary tumors and distantmetastasis when compared withmice that ...