{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Thyroid transcription factor-1 (TTF-1) is a protein that regulates transcription of genes specific to the development and function of the thyroid, lung and diencephalon. It is also known as thyroid-specific enhancer binding protein and NKX2.1. TTF-1 positive cells are found in Type II pneumocytes and Clara cells in the lung. In the thyroid, follicular and parafollicular cells are positive for TTF-1. In the context of lung cancer, TTF-1 is frequently expressed lung adenocarcinoma."}]}]}