Abstract:  lnsulin-like growth factor (IGF) system is growth factors with multiple bioactivities, such as regulating cell proliferation and differentiation, and inhibiting apoptosis and so on. In vivo and in vitro experiments have confirmed that IGF system takes part in the malignant transformation of cells and is related to the growth, invasion and metastasis of toumor. IGF system will be applied to early screening and target therapy for colorectal cancer.