Analogical to normal glandular prostate epithelium, Collins et al. distinguished immature stem (α2β1-integrin+/CD133+) and transit-amplifying cells (α2β1-integrin+/CD133−) in human prostate cancer specimens by clonogenic, proliferative and differentiating capacity in vitro[14]. The gene discussed is PROM1; the disease is prostate carcinoma.