Thyroid Transcription Factor-1 (TTF-1)

Abstract

Thyroid transcription factor 1 (TTF-1), as noted earlier, is a“thyroid specific”transcription factor that is a homeodomain-containing protein responsible for transcriptional activation of thyroid-specific genes, thyroglobulin (Tg), thyroperoxidase (TPO), and thyrotropin receptor (TSHr) genes, in thyroid follicular cells. Little is known about the histological localization or distribution of TTF-1 protein and mRNA, even though many papers on TTF-1 have been published in the past ten years. Therefore, we decided to examine the expression of TTF-1mRNA in normal and neoplastic thyroid tissues using immunohistochemistry and in situ hybridization as well as molecular techniques such as Northern blot and RT-PCR. In addition, extrathyroidal expression of TTF-1 was also investigated in some organs. In this paper, we reviewed literature and discussed the role of TTF-1 in thyroid hormonogenesis, and presented its precise localization or distribution in normal and neoplastic thyroid tissues. In addition, extrathyroidal expression of TTF-1 is briefly discussed.