Expression of miR-27a-3p is an independent predictive factor for recurrence in clear cell renal cell carcinoma.

MicroRNAs (miRNAs) are noncoding RNAs that regulate gene expression and function in tumor development and progression. We previously identified up-regulated miRNAs in clear cell renal cell carcinoma (ccRCC) compared to matched-pair normal kidney by microarray. Here, we identify miRNAs that are up-regulated in ccRCC and are also correlated with survival and/or recurrence. Twenty-four samples from ccRCC patients who underwent nephrectomies between 2011 and 2012 were divided into two groups: one of eleven patients who experienced recurrence (Group 1), and one of thirteen patients with no evidence of disease (Group 2) 2 years after surgery. Analyzing 22 miRNAs that were up-regulated in ccRCC in our previous study, we identify five miRNAs that were statistically up-regulated in Group 1 versus Group 2 by quantitative real-time PCR. We then evaluated these miRNAs in an independent cohort of 159 frozen ccRCC samples. High levels of miR-27a-3p (p < 0.01) correlated with a worse progression-free survival rate. Multivariate analysis revealed that miR-27a-3p was an independent predictive factor for recurrence. For functional analysis, miR-27a-3p controlled cell proliferation, migration and invasion in RCC cell lines. MiR-27a-3p could act as oncogenic miRNA and may be a candidate for targeted molecular therapy in ccRCC.