Identification of miR-140-3p as a marker associated with poor prognosis in spinal chordoma.

Objective: To investigate the expression profile of miR-140-3p in formalin-fixed paraffin-embedded (FFPE) tissues of spinal chordoma, and its correlation with the prognosis of spinal chordoma patients.

Methods: Dysregulated miRNAs in FFPE tissues of spinal chordoma were identified by microarray analysis. MiR-140-3p expression in surgically removed spinal chordoma tissues of 42 spinal chordoma patients (27 males and 15 females, aged 29-76 years) and corresponding nucleus pulposus tissues of 14 patients with disc herniation as the healthy control group (8 males and 6 females, aged 24-73 years) was measured by real-time quantitative RT-PCR assay. The association of miR-140-3p expression with clinicopathologic characteristics of spinal chordoma patients was analyzed. Additionally, we investigated the prognostic significance of miR-140-3p with the use of Kaplan-Meier methods and a Cox proportional hazard model.

Results: The expression of miR-140-3p was significantly higher in chordoma tissues than nucleus pulposus tissues (t = 3.530, P = 0.001). The expression of miR-140-3p positively correlated with surrounding muscle invasion. The Kapan-Meier survival analysis showed that the patients with high miR-140-3p expression had a significantly worse recurrence-free survival than those with a low expression (χ (2) = 31.270, P = 0.000, log-rank test). In addition, univariate and multivariate analyses for recurrence-free survival showed that miR-140-3p expression was an independent prognostic factor for patients with spinal chordoma (HR = 1.361, 95% CI: 1.135-1.633, P = 0.001).

Conclusion: Over-expression of miR-140-3p is correlated with recurrence and tumor invasion, suggesting that miR-140-3p could be a new predictor for recurrence and prognosis in patients with spinal chordoma.