Immunohistochemical stains for cytokeratin 7 (CK7), cytokeratin 20 (CK20), epithelial membrane antigen (EMA), polyclonal carcinoembryonic antigen (CEA), CA 19-9, CD10, CD56, renal cell carcinoma marker (RCC), hepatocellular carcinoma marker (HCC), vimentin, p53, Ki-67, TTF-1, estrogen receptor (ER), progesterone receptor (PR), and chromogranin A were all performed using standard avidin-peroxidase techniques. The gene discussed is TTF1; the disease is hepatocellular carcinoma.