Defining cell lineages in the prostate epithelium.

Understanding the stages of cell differentiation in the normal prostate epithelium is essential for the identification of the cell type(s) involved in prostatic carcinogenesis. Prostate glands are composed of three types of epithelial cells (i.e., basal, secretory and neuroendocrine) but the hierarchical relations among these cell types have been long controversial. We have recently developed a novel system to define prostate epithelial cell lineages in vivo. We find that, during normal prostate organogenesis, terminally differentiated secretory cells derive from p63-positive basal cells, which thus represent/include prostate stem cells. Future studies will determine if p63-positive basal cells retain stem cells capabilities in the adult prostate epithelium.