IGF1 and cancer: This prospective study aimed to determine the levels of IGF-1 and IGFBP-3 both intranodular and in the serum of patients with nodules in the thyroid gland who were planned to undergo biopsy, to investigate the relationship between expression of IGF-1 and thyroid nodule, and to evaluate the role of IGF-1 in differential diagnosis and pathogenetic function of benign and malignant thyroid nodules.