CEACAM5 and neoplasm: On immunocytochemistry the tumor cells were positive for carcinoembryonic antigen (CEA), synaptophysin, GATA3, and ER (5/8), focally positive for cytokeratin (CK) 7 and gross cystic disease fluid protein 15 (GCDFP-15), and negative for thyroid transcription factor 1 (TTF-1), calcitonin, thyroglobulin, CK20, PR, and HER2.