Abstract: ObjectiveTo explore the roles of biomarkers of the ratios of microRNA (miRNA) in osteosarcoma. MethodsThe blood samples from 20 patients with osteosarcoma and 30 healthy people with similar age were choosed. The miRNA expression profiles were filtered by gene chips of high flux. The results were verified by qRTPCR. The miRNA expression ratio was analysed by receiver operating characteristic (ROC) curve aiming to find the most predictive potential combinationtype markers. ResultsTwo hundred and fiftyeight miRNAs were found to be significantly deregulated in blood samples from 30 patients with osteosarcoma as compared with their matching normal blood samples (F=5.564, P＜0.05). Four miRNAs were choosed from blood samples of 22 patients with osteosarcoma and normal blood samples. MiR181b, miR199b5p and miR451 were significantly higher than that in normal blood sample (F=6.283，P＜0.05), while miR124 showed low expression (F=7.201，P＜0.05). Furthermore, the ratio of miR199b5p/miR124 showed a high sensitivity (96%) and specificity (97%). ConclusionThe abnormal expression of miRNA in osteosarcoma makes it have a predictive effect. The ratio of miR199b5p/miR124 could be served as combinationtype biomarkers in the diagnosis of osteosarcoma.

Key words: MicroRNAs, Osteosarcoma, Biological markers