A Validation Study for the Utility of Serum microRNA as a Diagnostic and Prognostic Marker in High-Grade Osteosarcoma Patients

Abstract In our previous study, high-grade osteosarcoma advanced locally and promoted metastasis by suppressing osteoclastogenesis via the upregulation of miR-146a-5p. Another 14 miRNAs in small extracellular vesicles were also detected 5 or more times as frequently in high-grade malignancy as in low-grade malignancy. However, the utility of these 15 miRNAs for determining the prognosis or diagnosis of osteosarcoma has not been validated in the clinical setting. We therefore aimed to assess the utility of these serum miRNAs as prognostic and diagnostic markers. Thirty osteosarcoma patients were retrospectively reviewed, excluding those with metastasis at presentation. The survival was compared according to the serum miRNA values. In addition, to confirm diagnostic competency for osteosarcoma, the serum miRNA values were compared with those in other bone tumor patients (n = 112) and healthy controls (n = 275). Osteosarcoma patients with high serum miRNA values paradoxically showed a better survival than those with low values. These patients also had higher values of serum miR-1261 than those with benign or intermediate-grade bone tumor. Serum miR-146a-5p may not be useful marker for determining the prognosis, and a larger investigation will be required to clarify its actual utility. In contrast, serum miR-1261 may be useful for differentiating benign or intermediate-grade bone tumor.