IFNG and Ewing sarcoma: The level of IFN-γ was significantly lower in patients with GCT (0.32 ± 0.02) compared to the patients with osteosarcoma (0.50 ± 0.03) and Ewing sarcoma (0.44 ± 0.01) (P < 0.0001) tumors; while the difference in the level of IFN-γ between patients with osteosarcoma and Ewing sarcoma was not statistically significant (Fig. 4C).