Epithelial cell differentiation pathways in the human prostate: Identification of intermediate phenotypes by keratin expression

The prostate grows slowly throughout adult life, leading to benign prostati c hyperplasia (BPH), which often results in urethral obstruction in later y ears. The symptoms of BPH are the second most common reason for surgery in men over 65. The aim of this study was to determine the relationship betwee n cell proliferation and cell differentiation in BPH tissue. Using multiple antibodies, simultaneously detected with different fluorophore-conjugated secondary antibodies, several subpopulations of epithelial cells were detec ted. In addition to K14, basal cells also expressed keratins 15, 17, and 19 in Various combinations, and some of the luminal cells also expressed K19 together with K8 and K18. Co-staining for cytokeratins and Ki-67 indicated that 44% of proliferative cells expressed K14 and 36% K19, although the dif ference was not statistically significant. This report provides a detailed description of the relationship between keratin expression and cell prolife ration in the prostate and indicates that K19-positive cells form the link between the basal and luminal layers of the epithelium.