Insulin-like growth factor 1; Insulin-like growth factor 2 (IGF-1; IGF-2)

Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 2 (IGF-2) are peptide hormones structurally similar to proinsulin, consisting of a single polypeptide chain (IGF-1: 70 amino acids; IGF-2: 67 amino acids)[4][6]. IGF-1 is produced mainly in the liver under growth hormone regulation and mediates most of its growth-promoting effects, whereas IGF-2 plays a dominant role in fetal development and tissue growth[7][3][5]. Both IGF-1 and IGF-2 bind to the IGF1R (a receptor tyrosine kinase) and to IR-A with high affinity, activating downstream signaling pathways (especially the PI3K/Akt pathway) to stimulate cell proliferation, inhibit apoptosis, and regulate metabolic homeostasis[4][3][2]. Aberrant IGF signaling is implicated in cancer progression, resistance to therapy, and other diseases, making both IGFs—and their receptor IGF1R—important drug targets and clinical biomarkers[9][4][3][7].

Other names

Somatomedin C (IGF-1)IGF-IIGF-II

Ligand blockade (preventing IGF1/IGF2 from binding IGF1R) - Receptor downregulation or inhibition of kinase activity - Induction of apoptosis in cancer cells by suppressing survival signaling pathways