Turning to DFS, SOX9 expression (RR 6.1, 95% CI, 1.3-13.9, P < 0.001), clinical stage (RR 1.8, 95% CI, 0.7–8.1, P = 0.03) and metastasis status (RR 2.9, 95% CI, 1.3–10.6, P = 0.02) were also independent prognostic markers for DFS of patients with osteosarcoma (Table 2). This evidence concerns the gene SOX9 and osteosarcoma.