Changes in microRNA expression levels correlate with clinicopathological features and prognoses in endometrial serous adenocarcinomas

This study aimed to determine the expression profiles of microRNAs (miRNAs) in endometrial serous adenocarcinoma and to examine the association between miRNA expression and clinical outcomes. Twenty-one patients diagnosed with endometrial serous adenocarcinoma between January 2001 and December 2006 were enrolled. miRNA expression profiles were examined using miRNA microarray and qRT-PCR. miRNA expression levels were correlated with clinicopathological variables and survival rates. A total of 120 miRNAs were differentially expressed in endometrial serous adenocarcinoma compared to normal endometria. Of these, 54 miRNAs were down-regulated (>2-fold), including miR-101, miR-10b*, miR-152, and miR-29b, and the remainder were up-regulated (>2-fold), including miR-200a, miR-200b, and miR-205. Decreased expression of miR-10b*, miR-29b, and miR-455-5p was correlated with vascular invasion (P = 0.048, P = 0.013, and P = 0.032, respectively). Univariate analysis revealed that lower expression of miR-101, miR-10b*, miR-139-5p, miR-152, miR-29b, and miR-455-5p was significantly correlated with poor overall survival (P < 0.05), and reduced expression of miR-152, miR-29b, and miR-455-5p was significantly correlated with poor disease-free survival (P < 0.05). Multivariate analysis demonstrated that decreased expression of miR-152 (P = 0.021) was a statistically independent risk factor for overall survival, and decreased expression levels of miR-101 (P = 0.016) and miR-152 (P = 0.010) were statistically independent risk factors for disease-free survival. In addition, transfection of miR-101 or miR-152 precursors into an endometrial serous carcinoma cell line inhibited cell growth (P < 0.0001 and P = 0.01, respectively). Moreover, strong positive immunoreactivity of cyclooxygenase-2 (COX-2) was significantly correlated with down-regulation of miR-101 (P = 0.035). These findings suggest that the dysregulation of miRNAs is associated with the poor prognosis in endometrial serous adenocarcinoma patients.