Transforming growth factor–B (TGF-B) isoforms are growth factors that function physiologically to regulate development, cellular proliferation, and immune responses. The role of TGF-B signaling in mammary tumorigenesis is complex, as TGF-B has been reported to function as both a tumor suppressor and tumor promoter. To elucidate the role of TGF-B signaling in mammary gland development, tumorigen...

MYB oncogene upregulation is associated with estrogen receptor (ER)-positive breast cancer, but disease requirements for MYB function in vivo have not been explored. In this study, we provide evidence of a critical requirement for MYB functions in models of human and murine breast cancer. In human breast cancer, we found that MYB expression was critical for tumor cell growth both in vitro and i...

Normal human mammary epithelial cells express hcx43 and hCx26 proteins, which form functional gap junction channels. Both Cx genes are transcriptionally down-regulated in mammary carcinoma cell lines; consequently, no protein is made and gap junctions are absent. This result suggests that the loss of gap junctional communication may play an important role in carcinogenesis. To address this ques...

Caveolin-1 (Cav-1) is a structural protein present in invaginations of the cell membrane. In human breast cancer, the cav-1 gene is believed to be a tumor suppressor gene associated with inhibition of tumor metastasis. However, little is known about its expression, regulation and function in canine mammary tumors. Expression levels of cav-1 were investigated using real-time PCR and immunoh...

The expression of mammary tumor virus (MTV) antigen in the milk and various organs of three non-inbred dd mouse stocks (ddO, ddN and ddY) was examined by the immunodiffusion (ID) and micro-immunodiffusion (micro-ID) tests. The rate of MTV antigen expression in the milk was 100% at the first lactation in ddO (6/6) and ddN mice (10/10), and 23% in ddY mice (3/13). Mammary tumor incidence was 13% ...

have published a series of reports indicating that sarcomas and carcinomas of mice, when frozen at †" 790 C. or when frozen and dried, retain the ability to induce, de novo, sarcomas in the connective tissue or carcinomas in the mammary tissues of the host†" depending upon the tumor used. The observations of Mann (17, 18) are particu @ larly pertinent to the present report. She subjected @ ...

As a step in the elucidation of human cancer immunity we studied antitumor activity of lymphoid cells by conducting a series of cultures using the primary culture of cells from spontaneous mammary cancers from C3H and RIll mice mixed with autochthonous lymphoid cells, and obtained the following results. 1) With 24 mammary tumors obtained from 24 mammary cancer. bearing mice, we prepared 22 susp...

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 ...

Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) encodes a tumor suppressor gene implicated in the growth of various tumor types including breast cancer. We previously demonstrated that recombinant adenovirus-mediated mda-7/IL-24 expression in the mammary glands of carcinogen-treated (methylnitrosourea, MNU) rats suppressed mammary tumor development. Since most MNU-induce...

Colony-stimulating factor (CSF)-1 is the primary regulator of tissue macrophage production. CSF-1 expression is correlated with poor prognosis in breast cancer and is believed to enhance mammary tumor progression and metastasis through the recruitment and regulation of tumorassociated macrophages. Macrophages produce matrix metalloproteases (MMPs) and vascular endothelial growth factor, which a...