ABSTRACT
Purpose To investigate the expression of RSK4 (ribosomal S6 protein kinase 4),CD44 and MMP-9 protein in primary renal cell carcinoma (pRCC) and metastatic renal cell carcinoma (mRCC),and to explore the level of expression as well as the association with clinicopathologic features and clinical outcome.Methods The expression of RSK4,CD44 and MMP-9 in 52 pRCC and 48 mRCC samples was detected by immunohistochemistry and its relationship with clinicopathologic features as well as prognosis was analyzed by statistical methods.Results In the 48 mRCC samples,there were 36 (75％,36/48),33(68.75％,33/48) and 44 (91.7％,44/48) positive for RSK4,CD44 and MMP-9,respectively,while the positive rate in 52 pRCC samples were 23 (44.2％,23/52),18 (34.6％,18/52) and 36 (69.2％,36/52),respectively.Statistical analysis showed that the expression of RSK4,CD44 and MMP-9 in mRCC samples was higher than the pRCC samples (PRsK4 =0.002,PMMP-9 =0.002,PcD44 =0.001).Furthermore,the expression of RSK4,CD44 and MMP-9 in mRCC samples was not correlated with ages,genders,Fuhrman grading and the metastatic sites (P ＞ 0.05).Further analysis showed that there was positive correlation among the three proteins (P =0.008),particularly,the expression of RSK4 and CD44 (P =0.019),MMP-9 and CD44 (P =0.05) were positively correlated,while the expression of RSK4 and MMP-9 (P =1.00) had no significance of correlation.Conclusion The expression of RSK4,CD44 and MMP-9 in mRCC samples is significantly higher than pRCC samples,suggesting that the three may mediate the metastasis of renal cell carcinoma,and its specific mechanism of action remains to be further studied.