Research From University Of Nebraska Has Provided New Data On Breast Cancer

NewsRx.com

October 1, 2009

According to a study from the United States, "The Janus kinase 2 (Jak2) is essential for normal mammary gland development, but this tyrosine kinase and its main effector, signal transducer and activator of transcription 5, are also active in a significant subset of human breast cancers. We have recently reported that Jak2 controls the expression and nuclear accumulation of cyclin D1."

"Because this particular D-type cyclin has been suggested to be a key mediator for ErbB2-associated mammary tumorigenesis, we deleted Jak2 from ErbB2-expressing mammary epithelial cells prior to tumor onset and in neoplastic cells to address whether this tyrosine kinase plays a role in the initiation as well as progression of mammary cancer. Similar to cyclin D1-deficient mice, the functional ablation of Jak2 protects against the onset of mammary tumorigenesis. In contrast, the deletion of Jak-2 from neoplastic cells or the acute, ligand-inducible down-regulation of this tyrosine kinase in an orthotopic transplant model did not affect the growth and survival of cancer cells. The constitutive activation of ErbB2 signaling, which is an initial event in the formation of mammary cancer, was able to override the functional role of Jak2 in regulating the expression of Akt1 and cyclin D1," wrote K. Sakamoto and colleagues, University of Nebraska.

The researchers concluded: "This might be a compensatory mechanism that explains why Jak2 is a relevant target for preventing the initiation but not the progression of ErbB2-associated mammary cancer. [Cancer Res 2009;69(16):6642-50]."

Sakamoto and colleagues published their study in Cancer Research (Targeting Janus Kinase 2 in Her2/neu-Expressing Mammary Cancer: Implications for Cancer Prevention and Therapy. Cancer Research, 2009;69(16):6642-6650).

For more information, contact K.U. Wagner, University of Nebraska Med Center, Eppley Institute Research Cancer & Allied Diseases, 985950 Nebraska Med Center, Omaha, NE 68198, USA.

Publisher contact information for the journal Cancer Research is: American Association Cancer Research, 615 Chestnut St., 17TH Floor, Philadelphia, PA 19106-4404, USA.

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