The progression of gliomas is associated with cancer stem cell phenotype

Since cancer stem cells in brain tumors were introduced, there have been few explanations regarding the role of cancer stem cells in the progression of glioma. Here, we investigated their major molecular changes in tumor progression in relation to the stem cell subpopulation. Using 12 surgical specimens of gliomatosis cerebri (GC) in the early and advanced stages, we measured the expression of a panel of cell proliferation, microvessel density, microvessel areas, angiogenic factors and their associated receptors. In addition, expression of neural stem cell markers and associated cytokines were examined in tumor tissues by quantitative real-time RT-PCR. Comparing the biological characteristics between the initial infiltrating lesions (n=7) and progressed lesions (n=5), Sox2 and Musashi-1 were expressed in the tumor tissue at an early and a progressed state. Contrary to the early infiltrative phase representing angiogenesis-independent growth, GC with progression showed that nestin (+), PCNA (+) cells and total vessel area (angioectasia) were markedly increased with a higher expression of proangiogenic molecules and their receptors. These results suggest that tumor progression is mediated by cancer stem cells and cross-talk of cancer stem cells along with their environment and are closely associated with angiogenesis-dependent progression and -independent growth.