Experimental Study On Inhibitory Effect Of RNAi On The Expression Of Her2/neu In Breast Cancer

Breast cancer is recognized as one of the most frequent malignant tumor in female, and in recent years, the morbility of breast cancer was sharply increased all of the world. Breast cancer was a systemic disease as well as some other tumors, and the recurrence and metastasis rate were about 50% after surgical operation. Even though the primary tumors within 1 cm diameter had the metastasis potent. There are no effective therapy methods when the breast cancer metastasis to a distant organ. Therefore, distant metastasis is the major lethal reason of breast cancer patients. In 1985, Coussens found a new tyrosine kinase(TK) gene on the cell surface, and the subtotal sequence was similar to the human Epidermal Growth Factor receptor(EGFR). Because it was similar to human Epidermal Growth Factor Receptor, it was named HER2. HER2 was proved to be tumorigenic oncogene and over-expressed by 20%～30% in the breast cancer, so it was considered one of the genes related to invasion, metastasis and prognosis of the breast cancer.HER2, also called c-erbB, belonged to the EGFR family,which had four members: erbB-1, erbB-2, erbB-3 and erbB-4. They were all transmembrane tyrosine kinase receptor and play important roles during the cell signal transduction. This family was the important regulator to the cell proliferation,...