MARKERS OF STEM CELLS IN GLIOMAS

Gliomas are the most common neoplasms of the Central Nervous System (CNS) and a frequent cause of mental impairment and death. Despite the improved responsiveness to primary therapy, survival of glioma patients is still very low. Therapies of malignant gliomas are often palliative because of their infiltrating nature and high recurrence. During the last decade, the concept that gliomas may arise from cancer stem cells (CSCs) has emerged. CSCs share with neural stem cells (NSCs) the capacity of cell renewal, multipotency and the expression of specific proteins, such as CD133 and nestin. This chapter describes similarities and differences between NSCs and CSCs, and summarizes the emerging knowledge on the possible role of stem cell markers as markers in gliomas, particularly in their tumoral grading. In addition, the importance of specific niches in maintaining pools of CSCs is considered. The involvement of signal transduction pathways, such as Notch, PDGF/PDGFR, Hedgehog-Gli1, and Bone morphogenetic protein and their implications in the control of CSCs function in gliomas are analyzed. Furthermore, certain proteins expressed in tumor migrating cells and possibly involved in recidive are evaluated.