Marker expression in HRPCa-2 by immunohistochemistry. In the area where tissue cores were taken to derive TSGs, we observed: (A-B) strong cytoplasmic K18 staining; (C-D) nuclear staining of AR; (E-F) cytoplasmic staining of PSA; (G-H) negative staining for the normal basal cell marker p63; positive staining for cytoplasmic AMACR (G-H) and negative ERG (I-J). In areas away from where tissue cores were taken in the same specimen, we observed nuclear ERG expression in low-grade cancer cells ( arrows in K) and staining for nuclear p63 in normal basal epithelial cells ( arrows in L). (B), (D), (F), (H), and (J) are higher magnification (40X) of boxed areas in (A), (C), (E), (G), and (I) (10X), respectively. The ERG-positive cells in (J) are endothelial cells, not cancer cells.