Serum level of microRNA-222 acts as a diagnostic and prognostic biomarker for osteosarcoma patients

Dysregulated expression profiles of microRNAs (miRNAs) and their roles in diagnosis and prognosis of osteosarcoma patients have attracted much attention. Although miR-222 has been shown to be important in several cancers, its roles in osteosarcoma remain unknown. Hence, in this study, we focused on the expression and further to evaluate the clinicopathological, diagnostic and prognostic value of miR-222 for osteosarcoma patients. The peripheral blood expres-sion of miR-222 in 57 pairs of osteosarcoma patients and corresponding healthy controls were estimated by quantita-tive real-time reverse transcription polymerase chain reaction (qRT-PCR), and the associations of miRNAs expression with clinicopathological factors, diagnostic and prognostic values of osteosarcoma patients were also analyzed. miR-222 levels in serum from osteosarcoma patients were significantly higher than those in healthy controls (P < 0.001). Importantly, miR-222 could efficiently screen osteosarcoma patients from healthy controls (AUC = 0.811). Then, the up-regulation of miR-222 more frequently occurred in osteosarcoma patients with large tumor size (P < 0.001), high TNM stage (P < 0.001) and positive distant metastasis (P < 0.001). Additionally, patients with high miR-222 expression had shorter overall survival (P < 0.001) and disease-specific survival (P < 0.001) than those with low expression. Moreover, high expression of miR-222 was an independent and significant prognostic factor for overall survival and disease-specific survival of osteosarcoma patients. Elevated expression of miR-222 in serum may be a novel biomarker for screening osteosarcoma patients and predicting poor prognosis of the disease. Therefore, serum miR-222 expression may have clinical potentials as a non-invasive diagnostic and prognostic biomarker for osteosarcoma patients.