Amplification and overexpression of the erbB-2 (HER-2/neu) proto-oncogene and exposure to the cell cycle mitogenic hormone estrogen (E2) have been associated with mammary tumorigenesis. Phytoestrogens found in soy act as selective estrogen receptor modulators and may also modify mammary carcinogenesis. We have used the wt-erbB-2 transgenic mouse model to study the effects of estrogen and dietar...

Melphalan (L-phenylalanine mustard), a cytostatic drug used in treatment of human breast cancer, was injected into mice bearing preneoplastic hyperplastic alveolar nodule mammary outgrowth line D2. Melphalan, doses of either 2.5 or 5.0 mg/kg, markedly enhanced tumor formation in its mammary nodule outgrowth line. Samples of nodule outgrowths in untreated mice produced 13% tumors by 9 months aft...

BACKGROUND The PEA3 Ets transcription factor is overexpressed in the vast majority of human breast tumors and in nearly all of those of the HER2/Neu-positive subclass. PEA3 is also overexpressed in various transgenic mouse models of this disease. Whether PEA3 plays an essential role in HER2/Neu-mediated oncogenesis has heretofore not been addressed. RESULTS Here, we report that each of the th...

Spontaneous mammary tumors occur in middle aged or senile dogs and are of three principal pathological types; a diffuse epithelial and connective tissue overgrowth often with associated cartilage and bone; solid masses of epithelial cells; intracystic papillomatous tumors. The metastases in this series were always composed of papillary carcinomatous cysts; this tissue in transplants to abdomina...

The purpose of this note is to emphasize and augment published descriptions of cytoplasmic inclusion bodies in mouse mammary tumors. First noted by Borrel in 1903, eosinophilic bodies were studied in some detail by Gu~rin (1955). Gu&in found inclusions most often in mammary tumors developing after whole-body irradiation of 3to 6-month-old female mice of low-tumor strain IC, and in some cases in...

Transgenic mice expressing the polyomavirus (PyV) middle T oncogene in the mammary epithelium develop multifocal mammary tumors that metastasize with high frequency. The potent transforming activity of PyV middle T antigen can, in part, be attributed to its ability to associate with and to activate a number of c-Src family tyrosine kinases (c-Src, c-Yes, and Fyn). As a first step toward assessi...

Breast cancer probably consists of a spectrum of diseases in terms of its hormonal dependence, as evidenced by the responses of patients to endocrine therapy. It is generally assumed that hormone-dependent breast cancers, which me spond to ovariectomy, would also respond to antiestrogen therapy. Studies in humans indicate a good correlation be tween the presence of estrogen receptor and respons...

There is abundant evidence that estrogens enhance the development of mammary tumors in high-cancer strains of mice, with the possible exception of the Marsh-Buffalo strain. The inhibitory effect of testosterone in this connection is also well known. Although similar studies in species other than the mouse have yielded conflicting results, there is evidence that estrogens enhance the development...

Susceptibility to mammary cancer in rats is genetically controlled by both susceptibility and suppressor genes. The Copenhagen (COP) rat strain is highly resistant to both spontaneous and induced mammary carcinogenesis. The resistant trait is due to the inheritance of an autosomal dominant allele termed mammary carcinoma suppressor (mcs) gene. To test whether the activity of mcs gene can suppre...

Whether the carcinogenic action of estrogen is an expression solely of its ability to establish and sustain a mammary gland or whether this hormone has in addition to mammary stimulation an independent carcinogenic property per se has been questioned (5). Desoxycortieosterone acetate has been reported to be as effective as estrogen in stimulating the development of mammary glands in young male ...