TPO and differentiated thyroid carcinoma: NG, nodular goitre: non-NG, without nodular goitre; TG, triglycerides; TC, total cholesterol; LDL, low-density lipoprotein; TSH, thyroid-stimulating hormone; Tg, thyroglobulin; CEA, carcinoembryonic antigen, PTC, papillary thyroid carcinoma; TPOAb: thyroid peroxidase antibodies; TGAb: thyroglobulin antibodies