Cancer Stem Cells in Brain Cancer

Several lines of evidence suggest that brain tumors arise from the ­transformation of a normal neural stem cell (NSC) or progenitor cell, which relies on the recognition of the many functional and genetic similarities shared by somatic stem cells and cancer cells. A minority population of human brain tumor initiating cells (BTICs) was identified through application of stem cell assays to brain tumors, and only these cells are able to recapitulate the patient tumor phenotype in an immunodeficient mouse model. Although the molecular mechanisms that regulate BTICs are still poorly understood, many of the signaling pathways that are active during development may be implicated as targets for transformation. BTICs have important implications for treatment, as these cells may evade current chemotherapy and radiotherapy. Further understanding of the role of BTICs in brain tumorigenesis may yield novel therapeutic agents aimed at targeting these rare cancer stem cells.