Prostate cancer stem cells

Stem Cells, Progenitor Cells, and Differentiated Cells Functional regeneration, the ability of cells to reconstitute the tissue of origin, is an essential biological property of many epithelia. This unique ability suggests the presence of a renewing cell type and reflects the homeostatic mechanism that normally replaces senescent cells or cells lost to tissue damage. Not all cells within a population are equally capable of reconstitution, and this activity has been attributed to the presence of a subset of tissue-specific stem and/or progenitor cells within various epithelia, including the breast, skin, intestine, and, of particular interest, the prostate. Cellular hierarchy is essential to the biology of complex multicellular organisms, and aberrant cell fate determination may result in pathological phenotypes. During embryogenesis, a phenomenal array of specialized cells arises from primitive, undifferentiated stem cells (SCs). The rapidly dividing cells of the early blastocyst inner-cell mass, and their derived cultured counterparts, termed embryonic stem cells (ESCs), exhibit pluripotency and unlimited proliferative potential. Both extrinsic signals and intrinsic properties converge to activate precise differentiation programs, thereby generating the phenotypically and functionally distinct lineage-restricted daughter cells present in the developing fetus. Growth and maturation require the continual activity of stem-like cells after birth. These somatic SCs also function to repair tissue damage and maintain tissue homeostasis over time. All SCs possess remarkable proliferative potential; however, unlike ESCs, somatic SCs rarely divide. Somatic SC division is constrained by interactions within a specialized stromal cell and extracellular matrix–rich environment (the SC niche).