NK2 homeobox 1 (TTF1) - Marker for lungcancer

The transcription factor encoded by the NKX2-1 gene is often referred to as TTF1 (thyroid transcription factor). This transcription factor, expressed during embryonic development, was initially described as a thyroid-specific protein where it functions to promote thyroid specific genes. TTF1 is also expressed in lung tissue where it plays a role in surfactant homeostatsis. Clinically, TTF1 is commonly used to distinguish primary lung cancer from metastases in the lung. Note that there is also another gene named TTF1 (transcription termination factor) that encodes a completely different protein, not known to be specifically involved in lung cancer.