Expression Of Rho Proteins(RhoA, RhoB And RhoC) In Human Laryngeal Carcinoma

ObjectiveHuman laryngeal carcinoma represents one of the most common tumor in head and neck , and the incidence rises apparently these years . Its incidence is relatively high in the north-east region of china. It is useful for us to explore new tumor biomarkers by studying the tumor related genes. Rho and Ras are both small GTPases, which are one of the signal transduction moleculars of cells. Rho GTPases play an important role in cellular processes as diverse as polarization , membrane trafficking ,cyto skeletal and transcriptional regulation and cell proliferation. Recent studies show that both RhoA and RhoC can transform the mouse fibroblast. It is proved that both RhoA and RhoC are over expressed in several tumor cells, and that both are expressed more when the tumor become more invasive. It appears that RhoB has taken a unique role among the Rho GTPases. Recent studies show that RhoB is vital for apoptosis induced by stress and for antitumor activity. RhoB expression is readily detected in normal epithelium, carcinomas in situ, and well-differentiated tumors, but it becomes too weak to be detected as tumor become deeply invasive and poorly differentiated. In order to study the expression of Rho proteins(RhoA, RhoB and RhoC) and their mRNA in human laryngeal carcinoma ,and periphery regions ,we perform this experiment.MethodsThe subjects were 51 patients who were diagnosed as laryngeal carcinoma and operated with laryngectomy in the NO.463 Hospital of PLA during February 2004 to June 2006. The expression of Rho proteins(RhoA, RhoB and RhoC) and their mRNA were examined with immunohistochemical method and RT-PCR method .ResultsIt is shown that the positive rate of RhoA protein in human laryngeal carcinoma is significantly higher than that in periphery regions .And the positive rate of RhoB protein in human laryngeal carcinoma is significantly lower than that in periphery regions . The positive rate of RhoC protein in human laryngeal carcinoma is significantly higher than that in periphery regions. The positive rate of RhoA and RhoC in carcinoma with node metastasis is significantly higher than that without node metastasis. The positive rate of RhoB in carcinoma with node metastasis is lower than that without node metastasis. It is shown that the expression of RhoA-mRNA in human laryngeal carcinoma is significantly higher than that in periphery regions. And the expression of RhoB-mRNA in human laryngeal carcinoma is significantly lower than that in periphery regions. And the expression of RhoC-mRNA in human laryngeal carcinoma is significantly higher than that in periphery regions. And it is noted that the expression of RhoA-mRNA, and RhoC-mRNA is positively correlated well with the clinical stages. And the expression of RhoB is negatively correlated with 0the clinical stages. The expression of the RhoA-mRNA and RhoC-mRNA in carcinoma with node metastasis group is significantly higher than that without node metastasis group.ConclusionsThe expression of Rho proteins (RhoA, RhoB and RhoC) plays a role in the growth, invasion and local node metastasis of human laryngeal carcinoma. RhoA and RhoC promote the formation, invation and lymph node metastasis as oncogenes; While RhoB inhibits the growth and local lymph node metastasis of human laryngeal carcinoma. And they may be used as biomarker for the growth, invasion and local node metastasis of human laryngeal carcinoma. It may be valuable as predictors for lymph node metastasis and prognostic. It is of great value for the gene therapy of human laryngeal carcinoma to study on the function and role on the tumor of RhoB protein.