Issues

The cover image shows a region (taken at approximately 200× magnification) of invasive prostatic adenocarcinoma glands infiltrating the prostatic stroma amongst benign/normal appearing prostatic glands/acini. Shown is an immunohistochemical stain against ERG (brown staining), which stains the tumor cell nuclei (indicated by arrows). Blue staining shows nuclei counterstained with hematoxylin. Note that benign endothelial cells are also positive for ERG (not specifically pointed out in the figure but apparent in the stroma as small nuclei with very strong intensity staining for ERG). Arrowheads show ERG positive adenocarcinoma cells partially replacing epithelium in benign acini/ducts. Four such partially involved benign glands are shown (denoted by numerals 1–4). These findings are supportive of the concept of retrograde colonization of benign/normal appearing acini/ducts by prostatic adenocarcinoma cells. It is expected that the tumor cells partially filling these acini/ducts may commonly undergo expansion over time to fully replace the benign epithelial cells. It is evident, therefore, that this spreading of invasive adenocarcinoma cells, which generally do have the appearance of malignant appearing cells on standard hematoxylin and eosin stained slides, into benign acini/ducts could lead to a misclassification of what is actually invasive adenocarcinoma as high grade PIN. See article by De Marzo et al. (beginning on page 648) for more information.