Overexpression of microRNA-100 predicts an unfavorable prognosis in renal cell carcinoma.

PURPOSE: Dysregulation of microRNA-100 (miR-100) has been reported to be involved in tumorigenesis and tumor progression of several cancer types. However, its expression patterns in tumors are controversial. The aim of this study was to investigate the expression and clinical significance of miR-100 in renal cell carcinoma (RCC).

METHODS: Real-time quantitative PCR was performed to detect the expression levels of miR-100 in 96 paired samples of RCC and adjacent non-cancerous renal tissues. Then, statistical analysis was performed to determine the associations of miR-100 expression with the clinical features and the prognosis of RCCs.

RESULTS: miR-100 expression was significantly higher in RCC tissues compared with adjacent non-cancerous renal tissues (5.3 ± 2.2 vs. 1.9 ± 0.8, P < 0.001). In addition, high miR-100 expression in RCC tissues was significantly associated with advanced tumor T stage (P = 0.005) and grade (P = 0.01), and the presence of metastasis (P = 0.008). Moreover, Kaplan-Meier analysis showed the significant differences in 5-year overall (50.0 vs. 83.3 %, P = 0.006) and tumor-specific survival (58.3 vs. 83.3 %, P = 0.008) for patients with high and low miR-100 expression, respectively. Furthermore, multivariable Cox regression analysis identified high miR-100 expression in RCC tissues as an independent poor prognostic marker of both overall (P = 0.01) and tumor-specific survival (P = 0.02) in patients with RCCs.

CONCLUSION: Our data offer convincing evidence that miR-100 overexpression strongly associates with advanced tumor progression and unfavorable clinical outcome of patients with RCC. miR-100 expression may be a useful prognostic marker for this disease.