IGF1 and cancer: In addition to acting as insulin sensitizers, PPAR agonists mediate in vitro and in vivo pleiotropic anticancer effects.The insulin-like growth factor (IGF) system has a role in cancer development and progression and in resistance to drug-induced apoptosis.It is now well established that the IGF system is dysregulated/overactivated (resulting from receptor and ligand abnormal expression) in a variety of human malignancies.