CD133, a novel marker for human prostatic epithelial stem cells

Stem cells are clonogenic cells with self-renewal and differentiation properties, which may represent a major target for genetic damage leading to prostate cancer and benign prostatic hyperplasia. Stem cells remain poorly characterised because of the absence of specific molecular markers that permit us to distinguish them from their progeny, the transit amplifying cells, which have a more restricted proliferative potential. Human CD133 antigen, also known as AC133, was recently identified as a haematopoietic stem cell marker. Here we show that a small population (approximately 1%) of human prostate basal cells express the cell surface marker CD133 and are restricted to the α₂β₁^hi population, previously shown to be a marker of stem cells in prostate epithelia (Collins, A. T., Habib, F. K., Maitland, N. J. and Neal, D. E. (2001). J. Cell Sci. 114, 3865-3872). α₂β₁ ^hi/CD133⁺ cells exhibit two important attributes of epithelial stem cells: they possess a high in vitro proliferative potential and can reconstitute prostatic-like acini in immunocompromised male nude mice.