IGF1 and IGF2 are highly expressed in CRC, and a variety of metabolic disorders such as obesity, dyslipidemia, hyperinsulinemia, and glucose homeostasis are common in these patients, making the IGF system a biomarker of human CRC susceptibility and prognosis (31–34). The gene discussed is IGF2; the disease is obesity due to melanocortin 4 receptor deficiency.