Upregulation of microRNA-221 (miR-221) has been reported to induce the malignant phenotype of human osteosarcoma, suggesting its potential as a therapeutic target for this malignancy. However, the role of miR-221 in diagnosis and prognosis of osteosarcoma has been well less elaborated. Our aim was to investigate the clinicopathological, diagnostic, and prognostic value of miR-221 in human osteosarcoma.

Expression levels of miR-221 in tumor tissues and patients’ sera obtained from 108 cases of primary osteosarcomas were detected by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR).

Compared with normal controls, the expression levels of miR-221 in osteosarcoma tissues and patients’ sera were both dramatically upregulated (both P=0.001). Then, receiver operating characteristics (ROC) analysis showed that serum miR-221 level could efficiently distinguish osteosarcoma patients from healthy controls (Area Under ROC Curve, AUC=0.844). Additionally, the serum level of miR-221 in osteosarcoma patients with positive distance metastasis (P=0.01) and advanced clinical stage (P=0.006) was significantly higher than those without distance metastasis and with early clinical stage. Moreover, we found that high serum miR-221 level was correlated with shorter recurrence-free survival (RFS) and overall survival (OS) than low level (both P=0.001). Multivariate survival analysis confirmed that serum miR-221 level was an independent prognostic factor influencing the survival of patients with osteosarcoma.

These findings reveal that miR-221 may play a crucial role in the occurrence and the progression of human osteosarcoma. More importantly, miR-221 may function as a promising marker for screening individuals with osteosarcoma and for identifying individuals with poor prognostic potentials.