TTF1 and neoplasm: Immunohistochemistry showed the tumor to be positive for AE1/AE3 (pancytokeratin), cytokeratin(CK)7, CK34βE12 (about 20% of tumor) and Wilms tumor gene 1 (WT-1), with nonspecific reactions for CK5/6, p63, carcinoembryonic antigen (CEA), estrogen receptor (ER) and vimentin, while CK20, thyroid transcription factor 1 (TTF-1), caudal type homeobox 2 (CDX2), gross cystic disease fluid protein-15 (GCDFP-15), calretinin, D2-40 and CD10 were negative (Figure 4).