IGF1R and neoplasm: Although more work remains to be done to understand the critical role of the IGF1R/IGF1 axis in regulating MDSCs activity, based on the above observations we can speculate that IGF1/IGF1R pathway may have a role in recruiting MDSCs at the tumor site, and also in the differentiation of their immunosuppressive and, therefore, pro-tumorigenic activities (Figure 2).