TG Antibody Cocktail / 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 negative. Adenocarcinomas of nonthyroid origin do not react with this antibody cocktail. It is useful in identification of thyroid carcinoma of the papillary and follicular types. Presence of thyroglobulin in metastatic lesions establishes the origin of the tumor. Thyroglobulin + calcitonin antibody, can identify medullary carcinomas of the thyroid. Furthermore, thyroglobulin + TTF1 antibody can be a reliable marker to differentiate between primary thyroid and lung neoplasms.