Immunohistochemistry further revealed it to be positive for Thyroid Transcription Factor 1 (TTF-1), Vimentin and Cytokeratin 7 (CK7) and negative for Napsin A, carcinoembryonic antigen (CEA), prostate-specific acid phosphatase (PSAP), prostate-specific antigen (PSA), Cytokeratin 20 (CK20) and CDX2 tumor markers. This evidence concerns the gene CEACAM5 and neoplasm.