Reduced Expression Of Mir-26b Is Associated With Poor Prognosis Of Osteosarcoma

Altered expression of microRNAs (miRNAs) has been implicated in the initiation and progression of cancer. MiR-26b acts as a tumor suppressor in many types of cancers including osteosarcoma (OS). However, the clinical significance of miR-26b is poorly known. Real-time PCR was performed to assess the expression levels of tissue/serum miR-26b in patients with OS and their respective controls. The Pearson correlation between tissue and serum miR-26b was calculated and the diagnostic value of serum miR-26b was evaluated by Receiver operating characteristic (ROC) curve analysis. Then Chi square test was used to find out whether there was any association between tissue/serum miR-26b expression level and the clinicopathological parameters. Overall survival (OS) and disease-free survival (DFS) were evaluated using Kaplan-Meier method. The expression level of tissue/serum miR-26b was both significantly downregulated in patients with OS (P<0.01), and tissue and serum miR-26b was highly correlated with each other (r=0.521, P<0.01). Serum miR-26b could discriminate OS patients from normal controls with high accuracy (AUC=0.931, P<0.01) and the expression level of serum miR-26b in OS patients was significantly increased following treatment (P<0.01). In addition, tissue/serum miR-26b expression was associated with various important clinicopathological parameters. Moreover, the OS patients in the low tissue/serum miR-26b expression group had a poorer OS and DFS (P<0.05). Our study demonstrated that tissue/serum miR-26b was downregulated in OS patients and associated with poor clinical outcome of this progressive malignancy, suggesting miR-26b plays a tumor suppressive role in OS development and might be a promising biomarker for OS.