RALY RNA Binding Protein-like Reduced Expression is Associated with Poor Prognosis in Clear Cell Renal Cell Carcinoma

The molecular mechanisms involved in the progression of clear cell renal cell carcinomas (ccRCCs) arestill unclear. The aim of this study was to analyse the relationships between expression of RALYL and clinicalcharacteristics. In 41 paired samples of ccRCCs and adjacent normal tissues, we used real-time qPCR to evaluatethe expression of RALYL mRNA. RALYL protein levels were determined in 146 samples of ccRCC and 37adjacent normal tissues by immunohistochemistry. Statistical analysis was used to explore the relationshipsbetween expression of RALYL and the clinical characteristics (gender, age, tumor size, T stage, N stage, M stage,survival times and survival outcome) in ccRCC. In addition, these patients were follow-up period 64 months(range: 4~116months) to investigate the influence on prognosis. We found significantly differences between ccRCCtissues and normal tissues (p<0.001, paired-sample t test) in mRNA levels of RALYL. Immunohistochemistryanalyses in 146 ccRCC samples and 37 adjacent normal tissues showed significantly lower RALYL protein levelsin ccRCC samples (χ2-test, p<0.001), inversely correlating with tumour size (p=0.024), T stage (0.005), N stage(p<0.001) as well as M stage (p=0.019), but not age (p=0.357) and gender (p=0.348) . Kaplan-Meier survivalanalysis demonstrated that people with lower level of RALYL expression had a poorer survival rate than thosewith a higher level of RALYL expression, significantly different by the log-rank test (p=0.011). Cox regressionanalysis indicated that RALYL expression (p=0.039), N stage (p=0.008) and distant metastasis (p<0.001) wereindependent prognosis factors for the overall survival of ccRCC patients. We demonstrated that the expressionof RALYL was significantly low in ccRCC and correlated with a poor prognosis in a large number of clinicalsamples. Our findings showed that RALYL may be a potential therapeutic target as well as a poor prognosticfactor.