IGF1 and obesity due to melanocortin 4 receptor deficiency: Elevated levels of insulin and insulin-like growth factors (IGFs), such as IGF-I, are important mechanisms underlying the association between obesity, diabetes, and pancreatic cancer.62 Insulin, IGF-1, and the insulin receptor-related receptor can form functional hybrids.63 IGF1 and IGF1 receptors are highly expressed in pancreatic cancer cells, and IGF2 imprinting is disrupted in many tumors.64