Regarding Ewing sarcoma, both metastatic tumors (0.3280) and recurrent tumors (0.3280) expressed a significantly higher level of IGF-1R compared to non-metastatic (0.1168) (P < 0.05) and non-recurrent tumors (0.1234) (P < 0.001), respectively (Figure 1E). This evidence concerns the gene IGF1R and Ewing sarcoma.