The tumor cells were positive for cytokeratin (CK) 7 and thyroid transcription factor-1, and negative for CK20, special AT-rich sequence-binding protein 2, and caudal type homeobox 2 (Fig. 2d–h), together indicating that the tumor was a metastatic lesion originating from the lung adenocarcinoma [16–19]. This evidence concerns the gene NKX2-1 and neoplasm.