NKX2-1 and non-small cell lung carcinoma: While the majority of human NSCLCs have robust expression of NKX2.1, a homeobox transcription factor which is routinely used as a marker of NSCLC [2], a subset of the KRAS-driven tumors was identified with reduced expression of NKX2.1 [3, 4] associated with mucinous characteristics and poor prognosis in NSCLC patients [5].