{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Thyroglobulin (Tg) is a 660 kDa, dimeric glycoprotein produced exclusively by mature thyroid tissue and stored within the follicular lumen. and used entirely within the thyroid gland. After oxidation by thyroid peroxidase, iodine is incorporated into Tg. Iodinated Tg can form monoiodothyrosine (MIT) and diiodothyrosine (DIT), which are direct precursors of thyroid hormones. The coupling reaction between MIT and DIT results in the production of thyroid hormones: triiodothyronine (T3) and thyroxine (T4). After TSH-dependent stimulation, colloid Tg undergoes endocytosis into thyroid follicular cells. Within the cells, protein cleavage leads to the disengagement of thyroid hormones from Tg. Thyroid hormones are then released into the bloodstream, where they can be bound to carrier proteins or remain free. Tg is generally reabsorbed into the follicular lumen. According to literature, the vast majority of follicular thyroid cancer expresses thyroglobulin, sometimes only focally."}]}]}