IGF1 and colorectal cancer: Many epidemiologic studies have found an association between glucose intolerance and increased risk of colorectal cancer.1-7 Insulin is thought to influence colorectal carcinogenesis through its links with the insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs), which are overexpressed in many tumors.6 An insulin-associated decrease in IGFBP-1 and resultant increase in free IGF-1 may increase the risk of colorectal cancer.1,6 Thus, carcinogenesis is considered to be promoted by hyperinsulinemia.