Hormone responsiveness of autonomous and diversely hormone-responsive mammary tumors of the rat was assayed in organ cultures by measuring DNA synthesis. Rat sera rich in hormones secreted by mammotropic pituitary cells were compared with sera of normal female and male and of ovariectomized and hypophysectomized rats. Mammotropic sera invariably stimulated DNA synthesis of hormoneresponsive tum...

Breast cancers exhibit high intertumoral heterogeneity in genetic alterations as well as histopathological and other phenotypic characteristics. The contribution of the initiating oncogenic mutation to tumor phenotype remains controversial, largely due to the technical difficulties in delivering genetic alterations into well-defined subsets of mammary epithelial cells. To examine how different ...

Spontaneous mammary tumors were seen in seven of the 12 breeding female rats aged 2 years. All mammary tumors were diagnosed as mammary dysplasia (MD). Bone mineral contents (BMC) and bone mineral density (BMD) of their lumbar vertebrae and femur were determined using dual energy X-ray absorptiometry (DXA). In rats with MD, body weight (BW), BMD of the lumbar vertebrae and BMC of the femur were...

The effect of 1,3,5(i 0)-estratriene-3,1 6a,i 7f@-triol(estriol), i ,3,5(i O)-estratriene-2,3-diol-i 7-one (2-hydroxyestrone), and 1,3,5(i 0)-estratriene-2,3,i 7$-triol (2-hydroxyestradiol) on the growth of dirnethylbenz(a)anthracene-induced mammary tumor and of R3230AC-transplantable mammary tumor was corn pared with that produced by estradiol benzoate treatment. Estriol showed minimal inhibit...

Monoclonal antibodies have been generated against disrupted mammary tumor viruses isolated from Mus musculus, Mus cervicolor, and Mus cookii. Monoclonal antibodies directed against the M.W. 36,000 external glycoproteins of these viruses demonstrate the presence of multiple epitopes, i.e., distinct antigenic determinants, within these glycoproteins. These epitopes represent type, group, and inte...

Overexpression and amplification of the neu (c-erbB2, ERBB2) protooncogene have been implicated in the development of aggressive human breast cancer. To directly assess the effect of mammary gland-specific expression of the neu protooncogene, transgenic mice carrying unactivated neu under the transcriptional control of the mouse mammary tumor virus promoter/enhancer were established. By contras...

Flow cytometric DNA analysis was performed on biopsies from 9 nonmalignant and 111 malignant (primary and metastatic) feline mammary lesions. In our series, 46.3% of the primary mammary carcinomas appeared to be aneuploid, whereas all but one benign breast lesion were diploid. The degree of aneuploidy in carcinomas was low, with a relatively high number of primary tumors (12 of 82) displaying h...

Canine mammary tumors have a diverse biological behavior, and therefore a varied need for adjuvant therapy. The established and well accepted individual prognostic factors such as grade, stage, size and histological subtypes provide reasonable guidelines for to recommend adjuvant therapy in dogs with mammary tumors, but the interactions of these factors are not well understood. Specifically, ho...

We tested the antineoplastic effect of the farnesyltransferase inhibitor L-744,832 in mammary and lymphoid tumors overexpressing the N-ras proto-oncogene in transgenic mice. Mice bearing mammary tumors were randomly assigned to receive daily 40 mg/kg s.c. injections of this compound (experimental group, n = 6) or vehicle (control group, n = 6) per day for 5.5 weeks. Treatment with the compound ...

Identifying genomic alterations driving breast cancer is complicated by tumor diversity and genetic heterogeneity. Relevant mouse models are powerful for untangling this problem because such heterogeneity can be controlled. Inbred Chaos3 mice exhibit high levels of genomic instability leading to mammary tumors that have tumor gene expression profiles closely resembling mature human mammary lumi...