According to Hers et al., the downstream signaling activates the PI3K and regulates Akt via PDK1, mediating metabolic effects, cell growth, proliferation, and cell survival .118 In adult tissues, IR is responsible for the metabolic functions and IGF-IR are mainly regulators of growth processes.124 Both receptors can overlap in their biological effects in cancer cells, thus latest therapeutical concepts maintain that targeting both IR and IGF-IR would be a better approach than targeting IGF-IR alone.122,125–127. This evidence concerns the gene IGF1R and cancer.