CD133

CD133 antigen also known as prominin-1 is a is_associated_with::glycoprotein that in humans is encoded by the PROM1 is_associated_with::gene. It is a member of pentaspan is_associated_with::transmembrane glycoproteins (5-transmembrane, 5-TM), which specifically localize to cellular protrusions. While the precise function of CD133 remains unknown, it has been proposed to act as an organizer of cell membrane topology.

Tissue distribution
CD133 is expressed in is_associated_with::hematopoietic stem cells, is_associated_with::endothelial progenitor cells, is_associated_with::glioblastoma, is_associated_with::neuronal and glial is_associated_with::stem cells, various pediatric brain tumors, as well as adult kidney, mammary glands, trachea, salivary glands, placenta, digestive tract, testes, and some other cell types.

Clinical significance
A CD133+ cell population in brain tumors is thought to be a is_associated_with::cancer stem cell (CSC) population, which is rare, undergoes self-renewal and differentiation, and can propagate tumors when injected into immune-compromised mice. However, subsequent studies have indicated the difficulty in isolating pure CSC populations. CD133+ is_associated_with::melanoma cells are considered a subpopulation of CSC a critical role in recurrence. Moreover, CD133+ melanoma cells are is_associated_with::immunogenic and can be used as an antimelanoma vaccination. In mice the vaccination with CD133+ melanoma cells mediated strong anti-tumor activity that resulted in the eradication of parental melanoma cells. In addition, it has also been shown that CD133+ melanoma cells preferentially express the RNA helicase is_associated_with::DDX3X. As DDX3X also is an immunogenic protein, the same anti-melanoma vaccination strategy can be employed to give therapeutic antitumor immunity in mice.