NKX2-1 is a homeodomain containing transcription factor, responsible for regulating normal development and maintaining physiological functions of the lung, thyroid, and central nervous system. NKX2-1 appears to play a dual role in lung carcinogenesis. In lung tumors, NKX2-1 expression is significantly amplified. NKX2-1 is required for survival of lung adenocarcinoma and considered as a lineage survival oncogene. However, loss of NKX2-1 promotes metastasis in mouse lung adenocarcinoma. Lower NKX2-1 expression in human lung carcinoma have worse prognoses, suggesting that NKX2-1 inhibits tumor metastasis and acts as a tumor suppressor.