Abstract:?Objective?To investigate the expression levels of serum exosomal long non-coding RNA (LncRNA) H19 in the patients with osteosarcoma, its relationship with clinicopathological parameters and its value in the diagnosis of osteosarcoma.?Methods?The expression levels of serum exosomal LncRNA H19 in 46 patients with osteosarcoma and 50 healthy controls were detected by real-time fluorescent quantitative PCR (RT-PCR). The levels of their serum MMP-9, VEGF and IGF-2 were detected by ELISA. The correlation of the levels of serum exosomal LncRNA H19 with clinicopathological parameters of the patients with osteosarcoma was analyzed, and the value of serum exosomal LncRNA H19 in the diagnosis of osteosarcoma was evaluated by the ROC curve.?Results?The expression levels of serum exosomal LncRNA H19 was significantly correlated with the course of osteosarcoma and the occurrence of distant metastasis (P<0.01), but not with the gender, age, residence and lesion location of the patients (P>0.05). The expression levels of serum exosomal LncRNA H19 in the patients with osteosarcoma were significantly higher than that in healthy controls (P<0.01). The area under the ROC curve (AUCROC), sensitivity and specificity of serum exosomal LncRNA H19 for the diagnosis of osteosarcoma were 0.881, 87.2% and 75.6%, respectively, which were higher than those of serum MMP-9, VEGF and IGF-2.?Conclusion?Serum exosomal LncRNA H19 may be a biomarker for the diagnosis, individualized treatment and therapeutic effict monitoring of osteosarcoma.