Figure 2.

Cancer Stem Cells and Therapeutic Opportunities. From a conceptual standpoint, applying stem cell thinking to cancer opens up new therapeutic opportunities. Self renewal, as a subset of proliferation, becomes a critical process for targeting. The stem cell's supportive niche can be attacked. If one can block stem cell generation of progeny that cause clonal expansion, perhaps tumor bulk progression can be slowed. Proliferation of tumor “progenitors”, if they are more rapidly proliferative than stem cells (unproven as of yet), will be an important target. Promotion of differentiation, particularly if terminally differentiated cell types can be generated, such as neurons, may be another useful strategy. Of course, killing all tumor cells, and particularly tumor stem cells should be a goal, by further sensitizing them to conventional therapy, or targeting molecular pathways responsible for stem cell behavior. Migration, a property of normal brain precursor cells, will be important to target, if this is also a property of the cancer stem cell.