GFAP and neoplasm: No other hormones (GH, TSH, ACTH, LH, FSH) were expressed by tumor cells, and the other markers, including S-100 protein (Fig. 3d), glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), cytokeratin AE1/AE3 (CK AE1/AE3), vimentin, p53, and bcl-2, were also negative by immunostaining.