Glioma cells with stem cell-like properties represent a minor subfraction of the total tumor cell population. These cells are highly chemo- and radioresistent and are held responsible for the inevitable recurrence of malignant gliomas. This review summarizes current strategies for targeting putative glioma stem cells. Target definition approaches comprise extrapolation and adaptation of therapies from general oncology, target identification by correlative molecular genetic analyses, and dedicated target discovery research. Targeting strategies include inhibition of tumor-specific signaling pathways, enhancement of tumor cell differentiation, radiosensitization, indirect targeting of the tumor stem cell niche, oncolytic virotherapy, and adhesion molecule blockade.
