Purpose: The CD133 antigen has been identified as a putative stem cell marker in normal and malignant brain tissues. In gliomas, it is used to enrich a subpopulation of highly tumorigenic cancer cells. According to the cancer stem cell hypothesis, CD133-positive cells determine long-term tumor growth and, therefore, are suspected to influence clinical outcome. To date, a correlation between CD133 expression in primary tumor tissues and patients' prognosis has not been reported. Experimental Design:To address this question, we analyzed the expression of the CD133 stem cell antigen in a series of 95 gliomas of various grade and histology by immunohistochemistry on cryostat sections. Staining data were correlated with patient outcome. Results: By multivariate survival analysis, we found that both the proportion of CD133-positive cells and their topological organization in clusters were significant (P < 0.001) prognostic factors for adverse progression-free survival and overall survival independent of tumor grade, extent of resection, or patient age. Furthermore, proportion of CD133-positive cells was an independent risk factor for tumor regrowth and time to malignant progression in WHO grade 2 and 3 tumors. Conclusions: These findings constitute the first conclusive evidence that CD133 stem cell antigen expression correlates with patient survival in gliomas, lending support to the current cancer stem cell hypothesis.

Purpose: Stem-like tumor cells comprise a highly tumorigenic and therapy-resistant tumor subpopulation, which is believed to substantially influence tumor initiation and therapy resistance in glioma. Currently, therapeutic, drug-induced differentiation is considered as a promising approach to eradicate this tumor-driving cell population; retinoic acid is well known as a potent modulator of differentiation and proliferation in normal stem cells. In glioma, knowledge about the efficacy of retinoic acid-induced differentiation to target the stem-like tumor cell pool could have therapeutic implications.Experimental Design: Stem-like glioma cells (SLGC) were differentiated with all-trans retinoic acid-containing medium to study the effect of differentiation on angiogenesis, invasive growth, as well as radioresistance and chemoresistance of SLGCs. In vivo effects were studied using live microscopy in a cranial window model.Results: Our data suggest that in vitro differentiation of SLGCs induces therapy-sensitizing effects, impairs the secretion of angiogenic cytokines, and disrupts SLGCs motility. Further, ex vivo differentiation reduces tumorigenicity of SLGCs. Finally, we show that all-trans retinoic acid treatment alone can induce antitumor effects in vivo.Conclusions: Altogether, these results highlight the potential of differentiation treatment to target the stem-like cell population in glioblastoma. Clin Cancer Res; 16(10); 2715-28. ©2010 AACR.

Purpose: In glioma-in contrast to various other cancers-the impact of T-lymphocytes on clinical outcome is not clear. We investigated the clinical relevance and regulation of T-cell infiltration in glioma.Experimental Design: T-cell subpopulations from entire sections of 93 WHO II-IV gliomas were computationally identified using markers CD3, CD8, and Foxp3; survival analysis was then done on primary glioblastomas (pGBM). Endothelial cells expressing cellular adhesion molecules (CAM) were similarly computationally quantified from the same glioma tissues. Influence of prominent cytokines (as measured by ELISA from 53 WHO II-IV glioma lysates) on CAM-expression in GBM-isolated endothelial cells was determined using flow cytometry. The functional relevance of the cytokine-mediated CAM regulation was tested in a transmigration assay using GBM-derived endothelial cells and autologous T-cells.Results: Infiltration of all T-cell subsets increased in high-grade tumors. Most strikingly, within pGBM, elevated numbers of intratumoral effector T cells (T eff , cytotoxic and helper) significantly correlated with a better survival; regulatory T cells were infrequently present and not associated with GBM patient outcome. Interestingly, increased infiltration of T eff cells was related to the expression of ICAM-1 on the vessel surface. Transmigration of autologous T cells in vitro was markedly reduced in the presence of CAM-blocking antibodies. We found that TGF-b molecules impeded transmigration and downregulated CAM-expression on GBM-isolated endothelial cells; blocking TGF-b receptor signaling increased transmigration.Conclusions: This study provides comprehensive and novel insights into occurrence and regulation of T-cell infiltration in glioma. Specifically, targeting TGF-b1 and TGF-b2 might improve intratumoral T-cell infiltration and thus enhance effectiveness of immunotherapeutic approaches. Clin Cancer Res; 17(13); 4296-308. Ó2011 AACR.

BackgroundAn accident or a catastrophic disease may occasionally lead to brain death (BD) during pregnancy. Management of brain-dead pregnant patients needs to follow special strategies to support the mother in a way that she can deliver a viable and healthy child and, whenever possible, also be an organ donor. This review discusses the management of brain-dead mothers and gives an overview of recommendations concerning the organ supporting therapy.MethodsTo obtain information on brain-dead pregnant women, we performed a systematic review of Medline, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). The collected data included the age of the mother, the cause of brain death, maternal medical complications, gestational age at BD, duration of extended life support, gestational age at delivery, indication of delivery, neonatal outcome, organ donation of the mothers and patient and graft outcome.ResultsIn our search of the literature, we found 30 cases reported between1982 and 2010. A nontraumatic brain injury was the cause of BD in 26 of 30 mothers. The maternal mean age at the time of BD was 26.5 years. The mean gestational age at the time of BD and the mean gestational age at delivery were 22 and 29.5 weeks, respectively. Twelve viable infants were born and survived the neonatal period.ConclusionThe management of a brain-dead pregnant woman requires a multidisciplinary team which should follow available standards, guidelines and recommendations both for a nontraumatic therapy of the fetus and for an organ-preserving treatment of the potential donor.

Caring for a brain dead potential organ donor requires a shift in critical care from the extensive treatment of increased intracranial pressure towards strategies to maintain donor organ function. Suboptimal, unstandardized critical care management of organ donors, however, is one of the main reasons for insufficient organ procurement. The pathophysiological changes following brain death entail a high incidence of complications including hemodynamic instability, endocrine and metabolic disturbances, and disruption of internal homeostasis that jeopardize potentially transplantable organs. Strategies for the management of organ donors exist and consist of the normalization of donor physiology. This has resulted in standardized efforts to improve the critical care delivered to potential organ donors, increasing not only the number, but also the quality of suitable organs and aiming at an optimal outcome for the recipients. In this review, we discuss the pathophysiological changes associated with brain death and present the current guidelines at our department, which are optimized based on available literature.

To study the clinical relevance of undifferentiated tumour cells in astrocytic gliomas we employed a large tumour tissue microarray (n=283) with corresponding clinical data and analyzed the expression of Nestin and Sox-2, which mark undifferentiated stem- and progenitor cells in the normal brain. Both markers were expressed abundantly and staining of nestin significantly increased with WHO grade. Further, nestin and Sox-2 immunoreactivity was significantly associated with tumour cell proliferation and nestin expression was independently associated with poor patient survival. Our findings suggest that immature glioma cells are involved in tumour growth and tumour progression and significantly impact on patient prognosis.

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Mutations in the gene encoding isocitrate dehydrogenase 1 (IDH1) have been identified in approximately 70-80 % of astrocytomas and oligodendrogliomas of WHO grades II and III, and in secondary glioblastomas. In addition, a low incidence of IDH2 mutations has been detected in these tumors, and the occurence of IDH1 and IDH2 mutations is mutually exclusive. For patients with anaplastic gliomas and glioblastomas with IDH1 mutations, overall survival was significantly longer than for patients with wild-type tumours. However, the prognostic value of IDH1 in low-grade gliomas remains ambiguous. IDH1 codon 132 and IDH2 codon 172 mutation status were determined by direct sequencing for a retrospective series of 100 patients with histologically diagnosed Astrocytomas WHO Grad II (A II), and investigated for association with patient outcome. For the patient cohort analysed, median progression-free survival (PFS) was 44.6 months (95 %-CI 1.0-267.0), time to progression (median time to malignant progression (TtMP) was 74.9 months (95 %-CI 1.6-236.2), and median overall survival (OS) was 81.4 months (95 %-CI 5.5-274.8). IDH1 mutations were identified in 79 % of the patients. IDH2 mutations were not observed. Univariate and multivariate analysis revealed no association between IDH1 mutation status and PFS, TtMP, and OS. Furthermore, there were no significant differences regarding PFS, TtMP, and OS between patients with and without IDH1 mutations who did not receive adjuvant treatment. The prognostic value of IDH1 mutations in low-grade astrocytomas is rather low compared with that in high-grade gliomas.