The expression significance of serum MiR-21 in patients with osteosarcoma and its relationship with chemosensitivity.

To investigate the expression level of serum microRNA-21 (miR-21) in 69 patients with osteosarcoma, to analyze the changes in miR-21 expression in the serum and tumor tissues before and after chemotherapy in patients with osteosarcoma, and to investigate the relationship between the expression of serum miR-21 in patients with osteosarcoma and chemosensitivity.Real-time polymerase chain reaction (RT-PCR) was used to detect the expression level of serum miR-21 in 69 patients with osteosarcoma before and after chemotherapy, and analyze the relationship between the expression of miR-21 with tumor necrosis grading and chemosensitivity. The expression level of programmed cell death protein 4 (PDCD4) in tumor tissues of patients with osteosarcoma before and after chemotherapy was detected by Western blot.The expression level of serum miR-21 in patients with osteosarcoma was significantly higher than that in normal control subjects. The expression of serum miR-21 before and after chemotherapy was positively correlated with the expression of miR-21 in the corresponding tissues. In the group where chemotherapy was effective (the effective group), expression levels of miR-21 in patients with osteosarcoma before and after chemotherapy were significantly different. After chemotherapy, the expression level of target genes of miR-21 was increased, and the follow-up results showed that the 5-year survival rate was relatively higher after surgery.The expression level of serum miR-21 in patients with osteosarcoma is closely related to the therapeutic effects of osteosarcoma, which can be used as one of the potential biomarkers and therapeutic targets for the diagnosis and prediction of osteosarcoma.