Interestingly, NKX2-1 (more commonly known as Thyroid Transcription Factor-1 or TTF-1), a common immunohistochemical marker of lung adenocarcinomas [39,40], was among the top 20 classification markers and had higher expression levels in lung SCC compared to HNSCC cancers. Here, NKX2-1 is linked to lung adenocarcinoma.