Thyroglobulin

Thyroglobulin (TG) is a large molecular glycoprotein synthesized and secreted by thyroid follicular epithelial cells. It can bind with activated iodine to form iodinated TG, which is stored in the follicular cavities. After the action of thyroid stimulating hormone, iodinated TG is catalyzed by hydrolases to form thyroid hormone, thereby promoting metabolism and development of the body. In clinical practice, TG is mainly used in the research and diagnosis of the primary and metastatic thyroid follicle derived tumor, including papillary carcinoma, follicular carcinoma, undifferentiated carcinoma, etc. Its expression level is down-regulated with the decreased degree of cancer cell differentiation, indicating that TG has potential prognostic value. However, TG can not effectively distinguish between the benign and malignant thyroid lesion, so it is often used in combination with CD56, CK19, TPO, Galectin-3, HBME-1, and other biomarkers. In addition, some scholars have found that TG can be expressed in medullary thyroid carcinoma, which is considered as an independent risk factor for poor prognosis of patients.