Lung and Thyroid Source ID - Immunohistochemistry: TTF-1

Immunohistochemical (IHC) assays detect the nuclear expression of the transcription factor TTF-1 (Thyroid Transcription Factor-1), also known as NKX2-1. This protein is naturally expressed in the nuclei of lung epithelial cells (type II alveolar cells and renal cells) and in thyroid follicular cells. It is primarily used as a marker for non-small cell lung cancer (especially adenocarcinoma) and thyroid cancer, and to help determine the origin of metastases (cancerous spread) of unknown source.