IGF1R and osteosarcoma: While comparing osteosarcoma tumors as a matter of tumor features, it was revealed that the IGF-1R mRNA level was significantly higher in metastatic tumors (0.5007) compared to non-metastatic tumors (0.1618) (P < 0.0001); however, the difference between recurrent (0.2710) and non-recurrent (0.2088) tumors was not statistically significant (Figure 1D).