The identification of a target that selectively marks BTICs may provide an effective means to eradicate therapy refractory tumor cells, thus delaying or preventing recurrence. Unfortunately, existing BTIC markers amenable to immunotherapy in adult gliomas, such as prominin 1 (PROM1; CD133), are also expressed by human neural stem and progenitor cells (29). This evidence concerns the gene PROM1 and central nervous system cancer.