%0 Journal Article
%T Current Strategies for Identification of Glioma Stem Cells: Adequate or Unsatisfactory?
%A Paola Brescia
%A Cristina Richichi
%A Giuliana Pelicci
%J Journal of Oncology
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/376894
%X Cancer stem cells (CSCs) were isolated in multiple tumor types, including human glioblastomas, and although the presence of surface markers selectively expressed on CSCs can be used to isolate them, no marker/pattern of markers are sufficiently robust to definitively identify stem cells in tumors. Several markers were evaluated for their prognostic value with promising early results, however none of them was proven to be clinically useful in large-scale studies, leading to outstanding efforts to identify new markers. Given the heterogeneity of human glioblastomas further investigations are necessary to identify both cancer stem cell-specific markers and the molecular mechanisms sustaining the tumorigenic potential of these cells to develop tailored treatments. Markers for glioblastoma stem cells such as CD133, CD15, integrin-¦Á6, L1CAM might be informative to identify these cells but cannot be conclusively linked to a stem cell phenotype. Overlap of expression, functional state and morphology of different subpopulations lead to carefully consider the techniques employed so far to isolate these cells. Due to a dearth of methods and markers reliably identifying the candidate cancer stem cells, the isolation/enrichment of cancer stem cells to be therapeutically targeted remains a major challenge. 1. Introduction The cancer stem cell hypothesis postulates that a small subpopulation of cancer cells possessing self-renewal characteristics are responsible for initiating and maintaining cancer growth. According to the CSC model, the large populations found in a tumor might represent diverse stages of differentiation. The biological characteristics shared by normal stem cells (NSCs) and CSCs mainly involve self-renewal and differentiation potential, survival ability, niche-specific microenvironment requirements, and specific homing to injury sites and may have important implications in terms of new approaches to cancer. The identification of new therapeutic targets based on the CSC model represents a great challenge. Glioblastoma multiforme (WHO grade IV) is the most aggressive among the brain tumors of adults and displays striking morphologic variation among different patients. GBM contains a mixture cell populations with high propensity to infiltrate throughout the brain (making complete surgical resection impossible). It has been demonstrated that the bulk of malignant cells in GBM is generated by rare fractions of self-renewing, multipotent tumor-initiating cells (CSCs) also called tumor-initiating cells or tumor-propagating cells [1, 2] responsible for tumor
%U http://www.hindawi.com/journals/jo/2012/376894/