Figure 3: GSC are capable of self-renewal and tumor initiation. A schematic diagram representing the proposed origin and activity of GSC. GSC are believed to originate from neural stem cells. Further research is needed to explore a potential origin for GSC from neural progenitor cells and terminally differentiated cells. GSC are capable of self-renewal through both symmetric and asymmetric cell division. It is this ability for self-renewal and proliferation that implicates GSC as a potential source for therapy resistance.