NKX2-1 and cancer: NKX2-1 was firstly known to contribute to normal lung cells differentiation (20, 21), later it was found to be a specific tissue marker in LUAD as patients carry increased NKX2-1 gene amplification and protein expression compared to normal cells (22), which was not identified in other cancers types of breast, prostate, colon and pancreas (23–25), indicating NKX2-1 was an oncogene specific for lung cancer, and now it's commonly used for differential diagnosis in clinical practice (26).