R&D Systems offers a range of products which can be used to detect the expression of neural stem cell markers. Changes in the expression levels of specific molecules can be used to indicate the presence of neural stem cells in studies focused on further differentiation toward specific neural lineages. Commonly used markers for neural stem cells include Nestin and SOX2. Nestin is a useful marker because although it is expressed predominantly in stem cells of the central nervous system (CNS), its expression is absent from nearly all mature CNS cells. The transcription factor SOX2 is known to be expressed at high levels in the neuroepithelium of the developing CNS and is thought to be centrally important for neural stem cell proliferation and differentiation. In addition to intracellular molecules, products are available to study proteins which are expressed at the cell surface, including ABCG2, FGF R4, and Frizzled-9.