IGF1 and cancer: Functionally, M2-type macrophages release immunosuppression factors such as IL-10, transforming growth factor (TGF)-β, and arginase 1, to exert immune effects and release stem cell inducers, such as IL-8, IL-10, IGF, TGF-β1, and pleiotrophin, to maintain cancer stemness [[132], [133], [134], [135], [136], [137], [138], [139]].