Immunohistochemical localization of keratin in human prostate

The localization of keratin was investigated in normal human prostate, benign prostatic hyperplasia (BPH), and prostatic adenocarcinoma using immunohistochemical technique on frozen tissue sections. The purpose of this study was to identify changes in the distribution patterns of keratin due to malignancy. In normal and benign tissue specimens, keratin was detected in the cytoplasm of basal cells and glandular epithelial cells. In the glandular epithelial cells keratin was found as a deposit of fine granules. In the basal cells, the positive staining for keratin had a uniform distribution in the scanty cytoplasm. In specimens of prostatic adenocarcinoma, the basal cells retained a strong positive reaction for keratin. The shapes and the distributions of basal cells were markedly different in malignant specimens. Basal cells formed a discontinuous layer and surrounded the population of neoplastic cells in tissue sections containing the cribriform patterns. The cells expressed characteristic protrusions into extracellular spaces between the cancer cells. Keratin-positive granules were demonstrated in the adenocarcinoma cells as well. These granules had slightly smaller sizes and were distributed randomly. The study demonstrates that the immunohistochemical localization of keratin provides a refinement for the characterization of cells in tissue sections of prostate.