LAUSR

OBJECTIVE Recent evidence suggests that circular RNAs (circRNAs) play important roles in multiple diseases, including cancer. Circ-NT5C2 was reported to be up-regulated in osteosarcoma. However, the clinical significance of circ-NT5C2 remains largely unclear. The aim of the current study was to investigate the value of circ-NT5C2 for the prognosis of patients with osteosarcoma. PATIENTS AND METHODS the expression of circ-NT5C2 in osteosarcoma tissues and corresponding normal tissues were explored by quantitative real-time polymerase chain reaction (qRT-PCR) experiments. The association of circ-NT5C2 expression with clinicopathological factors or the prognosis of osteosarcoma patients was also analyzed. Kaplan-Meier survival analysis was performed to analyze the association of circ-NT5C2 expression with overall survival (OS) and disease-free survival (DFS) of patients. Univariate and multivariate Cox-regression analyses were used to identify risk factors for poor prognosis. RESULTS Our data showed a significant increase of circ-NT5C2 expression in osteosarcoma tissues compared with adjacent normal bone tissues (p < 0.01). In addition, we found that the level of circ-NT5C2 in osteosarcoma was strongly correlated with clinical stage (p = 0.006) and distant metastasis (p = 0.001). Importantly, patients with high expression of circ-NT5C2 had a shorter OS (p = 0.006) and DFS (p = 0.001) than those with low expression of circ-NT5C2. Finally, Cox regression analyses showed that high circ-NT5C2 expression might be an independent prognostic parameter to predict poor prognosis. CONCLUSIONS Our findings indicated that circ-NT5C2 is significantly up-regulated in osteosarcoma tissues. Circ-NT5C2 may represent a new marker of prognosis in osteosarcoma.