Figure 1

Immunohistochemical doublestaining for ERG and tumor-associated trypsin inhibitor (TATI). The upper panel shows a core representing a case of prostate cancer positive only for TATI (red staining). TATI is expressed in the cytoplasm of tumor cells. The lower panel shows a core with tumor cells with a cribriform growth pattern and exclusively positive for ERG, which is expressed in the nuclei of the tumor cells.