In tumors, variable levels of NKX2-1 expression are detected in 40–50% of non-small cell lung carcinomas (NSCLCs), being higher in lung adenocarcinomas than in squamous cell carcinomas, suggesting that levels of NKX2-1 expression are linked to tumor cell phenotypes [3], [4]. This evidence concerns the gene NKX2-1 and squamous cell carcinoma.