TG Antibody / Thyroglobulin

Thyroglobulin is a 660kDa dimeric pre-protein with mutiple glycosylation sites, detected at ~300kDa in western blot. It is produced by and processed within the thyroid gland to produce the hormone thyroxine and triiodothyronine. Prior to forming dimers, thyroglobulin monomers undergo conformational maturation in the endoplasmic reticulation. The vast majority of follicular carcinomas of the thyroid will give positive immunoreactivity for thyroglobulin antibody even though sometimes only focally. Poorly differentiated carcinomas of the thyroid are frequently thyroglobulin antibody negative. Adenocarcinomas of other-than-thyroid origin do not react with this antibody. This antibody is useful in identification of thyroid carcinoma of the papillary and follicular types. Presence of thyroglobulin in metastatic lesions establishes the thyroid origin of tumor. Thyroglobulin antibody, combined with calcitonin antibody, can identify medullary carcinomas of the thyroid. Furthermore, thyroglobulin antibody, combined with TTF1 antibody, can be a reliable marker to differentiate between primary thyroid and lung neoplasms.