IGF1 and glioblastoma: Furthermore, since downregulating IGF-1 or IGF-1R has been found to enhance the immunogenicity of GBM models in rats and a small clinical study in astrocytoma [155,156,157], possibly partly contributed by inducing tumor cell death to release tumor-specific antigens [158], further investigation of the anti-tumor efficacy of combining ICIs with anti-IGF strategies is also warranted.