Figure 4

Immunohistochemically, the carcinoma cells are clearly positive for CK7 (a), ER (b), while many stromal cells show positive reaction for inhibin-α (c) (Case 3). Expression of steroid factor-1 (SF-1), which is a transcription factor alternatively termed adrenal 4-binding protein (Ad4BP) to regulate expression of all steroidogenic enzymes[9], is predominant in the stromal cells but minimal in epithelial cells (Case 1).