Expression Of Rb And P-Rb In Breast Cancer Tissues And Their Significance In TGF-β Induced Epithelial-Mesenchymal Transition

As a tumor suppressor gene, Retinoblastoma gene (Retinoblastoma, Rb) can result in the destruction of the connection between cells and induce cell phenotype into mesenchymal cells.Objectives:To investigated the expression of RB, P-Rb, CDH1 and Vimentin in human breast cancer tissues and their significance during the process of epithelial-mesenchymal transition (EMT).Methods:Immuno-histochemistry was used to examine the expression of RB, P-Rb, CDH1 and Vimentin in 65 cases of breast cancer tissues. The correlation between their expression and the clinicopathological parameters was analyzed. Secondly,Real-time PCR and Western blot were used to examine the expression of Rb and P-Rb in TGFβ-induced EMT.Results:The expression rate of Rb and P-Rb in breast cancer tissues was 55.4% and 50.8%, respectively. The expression rate of CDH1 and Vimentin in breast cancer tissues was 76.9% and 43.1%, respectively. The expression of P-Rb and Vimentin was positively associated with tumor size, clinical stage and lymph node metastasis. CDH1 expression was negatively associated with tumor size, clinical stage and lymph node metastasis. The expression of Rb and P-Rb was positively correlated with CDH1 expression, but negatively correlated with Vimentin expression. The overall 5-year survival of breast cancer patients with P-Rb or Vimentin expression was significantly lower than patients without P-Rb or Vimentin expression. The overall 5-year survival of breast cancer patients with CDH1 positive expression was significantly higher than patients without CDH1 expression. Rb was down-regulated and P-Rb was up-regulated in TGF(3 induced EMT of HMLE cells.Conclusion:Inactivation of Rb promoted EMT and correlated with breast cancer metastasis.