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Yung, W. K. A. — Thu, 01 Oct 2009 15:49:24 PDT

Analysis of microsatellite instability in medulloblastoma

Thu, 01 Oct 2009 15:49:24 PDT

Medulloblastoma is the most common malignant brain tumor in children. The presence of microsatellite instability (MSI) in brain tumors, particularly medulloblastomas, has not been properly addressed. The aim of the present study was to evaluate the role of MSI in medulloblastoma carcinogenesis. MSI status was determined in 36 patients using a pentaplex PCR of quasimonomorphic markers (NR27, NR21, NR24, BAT25, and BAT26). Methylation status of mismatch repair (MMR) genes was achieved by methylation-specific multiplex ligation-dependent probe amplification (MLPA). In addition, MutS homolog 6 (MSH6) expression was determined by immunohistochemistry. Mutations of 10 MSI target genes (TCF4, XRCC2, MBD4, MRE11, ATR, MSH3, TGFBR2, RAD50, MSH6, and BAX) were studied by pentaplex PCR followed by analysis with GeneScan 3.7 software. Mutation analysis of hotspot regions of β-catenin (CTNNB1) and BRAF (v-raf murine sarcoma viral oncogene homolog B1) oncogenes was performed by PCR single-strand conformation polymorphism analysis followed by direct sequencing. Among the 36 tumors, we found four (11%) cases with instability, one with high MSI and three with low MSI. Methylation analysis of MMR genes in cases presenting shifts on the MSI markers revealed mild hypermethylation of MSH6 in 75% of cases, yet MSH6 was expressed in all the tumors. The MSI target genes MBD4 (methyl-CpG binding domain protein 4) and MRE11 (meiotic recombination 11 homolog A) were mutated in two different tumors. No CTNNB1 or BRAF mutations were found. This study is the most comprehensive analysis of MSI in medulloblastomas to date. We observed the presence of MSI together with mutations of MSI target genes in a small fraction of cases, suggesting a new genetic pathway for a role in medulloblastoma development.

Plasma IGFBP-2 levels predict clinical outcomes of patients with high-grade gliomas

Thu, 01 Oct 2009 15:49:24 PDT

Insulin-like growth factor binding protein 2 (IGFBP-2) is a malignancy-associated protein measurable in tumors and blood. Increased IGFBP-2 is associated with shortened survival of advanced glioma patients. Thus, we examined plasma IGFBP-2 levels in glioma patients and healthy controls to evaluate its value as a plasma biomarker for glioma. Plasma IGFBP-2 levels in 196 patients with newly diagnosed glioma and 55 healthy controls were analyzed using an IGFBP-2 ELISA kit. Blood was collected before surgery, after two-cycle adjuvant chemotherapy, and at recurrence. Plasma IGFBP-2 levels were correlated with disease-free survival (DFS) using Cox regression analyses. We found that preoperative plasma IGFBP-2 levels were significantly higher in high-grade glioma patients (n = 43 for grade III glioma; n = 72 for glioblastoma multiforme [GBM]) than in healthy controls (n = 55; p < 0.001) and low-grade (grade II) glioma patients (n = 81; p < 0.001). No significant differences in preoperative plasma IGFBP-2 levels were observed between grade III glioma and GBM patients or between grade II glioma patients and healthy controls. After recurrence, plasma IGFBP-2 levels were significantly increased in GBM patients (n = 26; p < 0.001). Preoperative plasma IGFBP-2 levels were significantly correlated with DFS in GBM patients (hazard ratio, 1.404; 95% confidence interval, 1.078–1.828; p = 0.012). We conclude that preoperative plasma IGFBP-2 levels are significantly higher in high-grade glioma patients than in low-grade glioma patients and healthy subjects, and are significantly correlated with recurrence and DFS in patients with GBM. Longitudinal studies with a larger study population are needed to confirm these findings.

Comparative analyses of gene copy number and mRNA expression in glioblastoma multiforme tumors and xenografts

Thu, 01 Oct 2009 15:49:24 PDT

Development of model systems that recapitulate the molecular heterogeneity observed among glioblastoma multiforme (GBM) tumors will expedite the testing of targeted molecular therapeutic strategies for GBM treatment. In this study, we profiled DNA copy number and mRNA expression in 21 independent GBM tumor lines maintained as subcutaneous xenografts (GBMX), and compared GBMX molecular signatures to those observed in GBM clinical specimens derived from the Cancer Genome Atlas (TCGA). The predominant copy number signature in both tumor groups was defined by chromosome-7 gain/chromosome-10 loss, a poor-prognosis genetic signature. We also observed, at frequencies similar to that detected in TCGA GBM tumors, genomic amplification and overexpression of known GBM oncogenes, such as EGFR, MDM2, CDK6, and MYCN, and novel genes, including NUP107, SLC35E3, MMP1, MMP13, and DDX1. The transcriptional signature of GBMX tumors, which was stable over multiple subcutaneous passages, was defined by overexpression of genes involved in M phase, DNA replication, and chromosome organization (MRC) and was highly similar to the poor-prognosis mitosis and cell-cycle module (MCM) in GBM. Assessment of gene expression in TCGA-derived GBMs revealed overexpression of MRC cancer genes AURKB, BIRC5, CCNB1, CCNB2, CDC2, CDK2, and FOXM1, which form a transcriptional network important for G2/M progression and/or checkpoint activation. Our study supports propagation of GBM tumors as subcutaneous xenografts as a useful approach for sustaining key molecular characteristics of patient tumors, and highlights therapeutic opportunities conferred by this GBMX tumor panel for testing targeted therapeutic strategies for GBM treatment.

MRI assessment of hemodynamic effects of angiopoietin-2 overexpression in a brain tumor model

Thu, 01 Oct 2009 15:49:24 PDT

Despite treatment efforts, the median survival in patients with glioblastoma multiforme, the most aggressive form of glioma, does not extend beyond 12–15 months. One of the major pathophysiological characteristics of these tumors is their ability to induce active angiogenesis. Thus, based on the lack of efficient therapies, agents that inhibit angiogenesis are particularly attractive as a therapeutic option. However, it has been recently proposed that although specifically targeting vascular endothelial growth factor, the main angiogenic factor, certainly leads to significant tumor regression, it could also be followed by tumor relapses. In this case, angiogenesis is driven by alternate pathways that include other angiogenic factors. One possible strategy to overcome this therapeutic obstacle is to overexpress antivascular factors such as angiopoietin-2 (Ang2). Here, by using MRI and histological analysis, we studied the vascular events involved in glioma growth impairment induced by Ang2 overexpression. Our results show that an increase in Ang2 expression, during the tumor growth, leads to a significant decrease in tumor growth (~86%) along with an increase in the survival median (~70%) but does not modify the tumor vascular area or cerebral blood volume. However, tumor Ang2-derived blood vessels display an abnormal, enlarged morphology. We show that the presence of Ang2 leads to an enhancement of tumor perfusion and a decrease in tumor vessel permeability. Based on our MR image evaluations of hemodynamic tumor vessel changes, we propose that Ang2-derived tumor vessels lead to an inadequate oxygenation of the tumor tissue, leading to impairment in tumor growth.

Efficacy and MRI of rituximab and methotrexate treatment in a nude rat model of CNS lymphoma

Thu, 01 Oct 2009 15:49:24 PDT

To determine the efficacy of methotrexate and/or rituximab in a CNS lymphoma model and to evaluate MRI modalities for monitoring efficacy, we inoculated female athymic nude rats (rnu/rnu) intracerebrally with human MC116 B-lymphoma cells. Between days 16 and 26, rats were randomized to receive intravenous (IV) treatment with (1) saline (controls, n = 15), (2) methotrexate 1,000 mg/m² (n = 6), (3) rituximab 375 mg/m² (n = 6), or (4) rituximab plus methotrexate (n = 6). T2/fluid-attenuated inversion recovery (FLAIR) and gadolinium contrast-enhanced T1 MRI sequences were performed prior to and 1 week after treatment. IV rituximab gave an objective tumor response in four of six animals (>50% reduction in tumor volume comparing pre- and posttreatment T2/FLAIR MRI) and resulted in stable disease (50%–125% of baseline) in another animal. The percent change in tumor volume on T2/FLAIR images was significantly different in the control versus rituximab group (p = 0.0051). IV methotrexate slowed tumor growth, compared to controls, but only one of six animals had an objective response. In untreated controls, tumor histological volumes correlated well with T2/FLAIR or contrast-enhanced T1 images (r = 0.877). In the treatment groups, T2/FLAIR correlation was good, but the gadolinium-enhanced T1 MRI was not significantly correlated with histology (r = 0.19). The MC116 CNS lymphoma model seems valuable for preclinical testing of efficacy and toxicity of treatment regimens. IV rituximab was highly effective, but methotrexate was only minimally effective. T2/FLAIR was superior to contrast-enhanced T1 for monitoring efficacy.

Identification of p53 as a strong predictor of survival for patients with malignant peripheral nerve sheath tumors

Thu, 01 Oct 2009 15:49:24 PDT

The purpose of this study was to identify new prognostic biomarkers with clinical impact in malignant peripheral nerve sheath tumor (MPNST), a highly aggressive malignancy for which no consensus therapy exists besides surgery. We have used tissue microarrays (TMAs) to assess in situ expression of 14 cell-cycle–regulating proteins in 64 well-characterized MPNST patients: 36 sporadic and 28 with neurofibromatosis type 1 (NF1). We developed a new software application for evaluation and logistics of the TMA images and performed a literature survey of cell cycle proteins in MPNST. For NF1-associated patients, there was a clear association between nuclear expression of p53 and poor survival (p = 0.004). Among the other proteins analyzed, we also found significant associations between survival and clinical variables, but none were as strong as that for p53. For the total series of MPNSTs, p53 was shown to be an independent predictor of survival, and patients without remission, with tumor size larger than 8 cm, and with positive p53 expression had a 60 times greater risk of dying within the first 5 years compared with the remaining patients (p = 0.000002). This is the most comprehensive study of in situ protein expression in MPNST so far, and expressed p53 was found to be a strong surrogate marker for outcome. Patients in complete remission with a primary p53-positive MPNST diagnosis may be considered in a high-risk subgroup and candidates for adjuvant treatment.

DC vaccination with anti-CD25 treatment leads to long-term immunity against experimental glioma

Thu, 01 Oct 2009 15:49:24 PDT

We studied the feasibility, efficacy, and mechanisms of dendritic cell (DC) immunotherapy against murine malignant glioma in the experimental GL261 intracranial (IC) tumor model. When administered prophylactically, mature DCs (DCm) ex vivo loaded with GL261 RNA (DCm-GL261-RNA) protected half of the vaccinated mice against IC glioma, whereas treatment with mock-loaded DCm or DCm loaded with irrelevant antigens did not result in tumor protection. In DCm-GL261-RNA–vaccinated mice, a tumor-specific cellular immune response was observed ex vivo in the spleen and tumordraining lymph node cells. Specificity was also shown in vivo on the level of tumor challenge. Depletion of CD8⁺ T-cells by anti-CD8 treatment at the time of tumor challenge demonstrated their essential role in vaccine-mediated antitumor immunity. Depletion of CD25⁺ regulatory T-cells (Tregs) by anti-CD25 (aCD25) treatment strongly enhanced the efficacy of DC vaccination and was itself also protective, independently of DC vaccination. However, DC vaccination was essential to protect the animals from IC tumor rechallenge. No long-term protection was observed in animals that initially received aCD25 treatment only. In mice that received DC and/or aCD25 treatment, we retrieved tumor-specific brain-infiltrating cytotoxic T-lymphocytes. These data clearly demonstrate the effectiveness of DC vaccination for the induction of long-lasting immunological protection against IC glioma. They also show the beneficial effect of Treg depletion in this kind of glioma immunotherapy, even combined with DC vaccination.

Radiation-induced meningiomas: A shadow in the success story of childhood leukemia

Thu, 01 Oct 2009 15:49:24 PDT

While the prognosis of acute childhood leukemia has improved, long-term survivors are increasingly experiencing late effects of the treatment. Cranially irradiated survivors are predisposed to the development of CNS tumors. Our aim was to describe the incidence of secondary brain tumors and to define the significance of treatment-related risk factors and host characteristics in a cohort of childhood leukemia survivors. Our cohort consisted of 60 consecutive cranially irradiated adult survivors of childhood leukemia treated in Oulu University Hospital (Oulu, Finland); MRI of the brain was performed on 49. The sites of the tumors, their histology, and details of the leukemia treatment were determined. Of the 49 patients, 11 (22%) 1–8 years of age at the time of diagnosis developed meningioma later in life, while no other brain tumors were seen. In this cohort, the development of meningioma seemed to show undisputable linkage with long latency periods (mean, 25 years; range, 14–34 years) and an increasing incidence 20 years after the treatment (47%). Three patients had multiple meningiomas, two had recurrent disease, and one had an atypical meningioma. Age at the time of irradiation, gender, or cumulative doses of chemotherapeutic agents showed no significant association with the development of meningiomas. The high incidence of meningiomas in this study was associated with long follow-up periods. Although the cohort is small, it seems probable that the increasing incidence of meningioma will shadow the future of cranially irradiated leukemia survivors. Systematic brain imaging after the treatment is therefore justifiable.

Role of a second chemotherapy in recurrent malignant glioma patients who progress on bevacizumab

Thu, 01 Oct 2009 15:49:24 PDT

Bevacizumab is a humanized monoclonal antibody against vascular endothelial growth factor (VEGF) that has efficacy in recurrent malignant gliomas, particularly in combination with irinotecan. However, responses are rarely durable. Continuation of bevacizumab in combination with another chemotherapeutic agent may demonstrate some activity. In this article we present a retrospective review of 54 patients with recurrent malignant gliomas who progressed on a bevacizumab-containing regimen and were then treated with an alternate bevacizumab-containing regimen. All patients received intravenous bevacizumab (5–10 mg/kg) every 2 weeks alone or in combination with an additional chemotherapeutic agent, such as irinotecan. There was no limit on the number of prior therapies. Clinical characteristics and outcomes were reviewed. Tumor progression was determined by a combination of clinical status and radiographic changes. Patients were 33 men, 21 women (median age, 50 years; range, 23–72 years) with a median KPS score of 80 prior to the first bevacizumab-containing regimen and 70 prior to the second regimen; median prior chemotherapy regimens including the first bevacizumab-containing regimen was 3 (range, 2–5). Median progression-free survival (PFS) on the first bevacizumab-containing regimen was 124 days (95% confidence interval [CI], 87–154 days); 6-month (6M)-PFS was 33%. Median PFS on the second bevacizumab-containing regimen was 37.5 days (95% CI, 34–42 days); 6M-PFS was 2%. Ten patients on the first regimen and 12 patients on the second regimen suffered grade 3/4 toxicities. Those patients with malignant gliomas who progressed despite a bevacizumab-containing regimen rarely responded to the second bevacizumab-containing chemotherapeutic regimen. In such patients, alternate therapies should be considered.

Phase I trial of temozolomide plus O6-benzylguanine 5-day regimen with recurrent malignant glioma

Thu, 01 Oct 2009 15:49:24 PDT

This phase I clinical trial conducted with patients who had recurrent or progressive malignant glioma (MG) was designed to determine the maximum tolerated dose (MTD) and toxicity of three different 5-day dosing regimens of temozolomide (TMZ) in combination with O⁶-benzylguanine (O⁶-BG). Both TMZ and O⁶-BG were administered on days 1–5 of a 28-day treatment cycle. A bolus infusion of O⁶-BG was administered at 120 mg/m² over 1 h on days 1, 3, and 5, along with a continuous infusion of O⁶-BG at 30 mg/m²/day. TMZ was administered at the end of the first bolus infusion of O⁶-BG and then every 24 h for 5 days during the continuous infusion of O⁶-BG. Patients were accrued to one of three 5-day dosing regimens of TMZ. Twenty-nine patients were enrolled into this study. The dose-limiting toxicities (DLTs) were grade 4 neutropenia, leukopenia, and thrombocytopenia. The MTD for TMZ for the three different 5-day dosing schedules was determined as follows: schedule 1, 200 mg/m² on day 1 and 50 mg/m²/day on days 2–5; schedule 2, 50 mg/m²/day on days 1–5; and schedule 3, 50 mg/m²/day on days 1–5 while receiving pegfilgrastim. Thus, the 5-day TMZ dosing schedule that maximized the total dose of TMZ when combined with O⁶-BG was schedule 1. This study provides the foundation for a phase II trial of O⁶-BG in combination with a 5-day dosing schedule of TMZ in TMZ-resistant MG.

Abstracts from the 2009 Joint Meeting of the Society for Neuro-Oncology (SNO) and the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Section on Tumors

Thu, 01 Oct 2009 15:49:24 PDT

SOCIETY NEWS

Pelloski, C. E. — Thu, 01 Oct 2009 15:49:24 PDT

IDH1 mutations are present in the majority of common adult gliomas but rare in primary glioblastomas

Thu, 06 Aug 2009 14:33:30 PDT

We screened exon 4 of the gene isocitrate dehydrogenase 1 (NADP+), soluble (IDH1) for mutations in 596 primary intracranial tumors of all major types. Codon 132 mutation was seen in 54% of astrocytomas and 65% of oligodendroglial tumors but in only 6% of glioblastomas (3% of primary and 50% of secondary glioblastomas). There were no mutations in any other type of tumor studied. While mutations in the tumor protein p53 gene (TP53) and total 1p/19q deletions were mutually exclusive, IDH1 mutations were strongly correlated with these genetic abnormalities. All four types of mutant IDH1 proteins showed decreased enzymatic activity. The data indicate that IDH1 mutation combined with either TP53 mutation or total 1p/19q loss is a frequent and early change in the majority of oligodendroglial tumors, diffuse astrocytomas, anaplastic astrocytomas, and secondary glioblastomas but not in primary glioblastomas.

Identification of regions correlating MGMT promoter methylation and gene expression in glioblastomas

Thu, 06 Aug 2009 14:33:30 PDT

The O⁶-methylguanine-DNA methyltransferase gene (MGMT) is methylated in several cancers, including gliomas. However, the functional role of cysteine-phosphate-guanine (CpG) island (CGI) methylation in MGMT silencing is still controversial. The aim of this study was to investigate whether MGMT CGI methylation correlates inversely with RNA expression of MGMT in glioblastomas and to determine the CpG region whose methylation best reflects the level of expression. The methylation level of CpG sites that are potentially related to expression was investigated in 54 glioblastomas by pyrosequencing, a highly quantitative method, and analyzed with respect to their MGMT mRNA expression status. Three groups of patients were identified according to the methylation pattern of all 52 analyzed CpG sites. Overall, an 85% rate of concordance was observed between methylation and expression (p < 0.0001). When analyzing each CpG separately, six CpG sites were highly correlated with expression (p < 0.0001), and two CpG regions could be used as surrogate markers for RNA expression in 81.5% of the patients. This study indicates that there is good statistical agreement between MGMT methylation and expression, and that some CpG regions better reflect MGMT expression than do others. However, if transcriptional repression is the key mechanism in explaining the higher chemosensitivity of MGMT-methylated tumors, a substantial rate of discordance should lead clinicians to be cautious when deciding on a therapeutic strategy based on MGMT methylation status alone.

Characterization and immunotherapeutic potential of {gamma}{delta} T-cells in patients with glioblastoma

Thu, 06 Aug 2009 14:33:30 PDT

Classical immunotherapeutic approaches to glioblastoma multiforme (GBM) have shown mixed results, and therapies focused on innate lymphocyte activity against GBM have not been rigorously evaluated. We examined peripheral blood lymphocyte phenotype, T-cell number, mitogenic response, and cytotoxicity against GBM cell lines and primary tumor explants from GBM patients at selected time points prior to and during GBM therapy. Healthy volunteers served as controls and were grouped by age. T-cell infiltration of tumors from these patients was assessed by staining for CD3 and T-cell receptor . Our findings revealed no differences in counts of mean absolute T-cells, T-cell subsets CD3⁺CD4⁺ and CD3⁺CD8⁺, and natural killer cells from healthy volunteers and patients prior to and immediately after GBM resection. In contrast, T-cell counts and mitogen-stimulated proliferative response of T-cells were markedly decreased prior to GBM resection and throughout therapy. Expanded/activated T-cells from both patients and healthy volunteers kill GBM cell lines D54, U373, and U251, as well as primary GBM, without cytotoxicity to primary astrocyte cultures. Perivascular T-cell accumulation was noted in paraffin sections, but no organized T-cell invasion of the tumor parenchyma was seen. Taken together, these data suggest that T-cell depletion and impaired function occur prior to or concurrent with the growth of the tumor. The significant cytotoxicity of expanded/activated T-cells from both healthy controls and selected patients against primary GBM explants may open a previously unexplored approach to cellular immunotherapy of GBM.

Lactate promotes glioma migration by TGF-{beta}2-dependent regulation of matrix metalloproteinase-2

Thu, 06 Aug 2009 14:33:30 PDT

Lactate dehydrogenase type A (LDH-A) is a key metabolic enzyme catalyzing pyruvate into lactate and is excessively expressed by tumor cells. Transforming growth factor-β2 (TGF-β2) is a key regulator of invasion in high-grade gliomas, partially by inducing a mesenchymal phenotype and by remodeling the extracellular matrix. In this study, we tested the hypothesis that lactate metabolism regulates TGF-β2–mediated migration of glioma cells. Small interfering RNA directed against LDH-A (siLDH-A) suppresses, and lactate induces, TGF-β2 expression, suggesting that lactate metabolism is strongly associated with TGF-β2 in glioma cells. Here we demonstrate that TGF-β2 enhances expression, secretion, and activation of matrix metalloproteinase-2 (MMP-2) and induces the cell surface expression of integrin _vβ₃ receptors. In spheroid and Boyden chamber migration assays, inhibition of MMP-2 activity using a specific MMP-2 inhibitor and blocking of integrin _vβ₃ abrogated glioma cell migration stimulated by TGF-β2. Furthermore, siLDH-A inhibited MMP2 activity, leading to inhibition of glioma migration. Taken together, we define an LDH-A–induced and TGF-β2–coordinated regulatory cascade of transcriptional regulation of MMP-2 and integrin _vβ₃. This novel interaction between lactate metabolism and TGF-β2 might constitute a crucial mechanism for glioma migration.

The role of the membrane cytoskeleton cross-linker ezrin in medulloblastoma cells

Osawa, H., Smith, C. A., Ra, Y. S., Kongkham, P., Rutka, J. T. — Thu, 06 Aug 2009 14:33:30 PDT

Medulloblastoma is a highly malignant brain tumor that occurs predominantly in children. The molecular pathogenesis of medulloblastoma is under investigation. Previously, we used complementary DNA microarray analysis to compare patterns of gene expression in medulloblastoma samples versus normal cerebellum. The cytoskeletal protein ezrin was found to be overexpressed in medulloblastoma compared with normal cerebellum, an observation that was further validated by immunohistochemistry and real-time PCR analysis. To assess the role of ezrin in medulloblastoma, we studied ezrin's role in medulloblastoma migration, invasion, and adhesion. Western blotting and immunofluorescence showed high expression of ezrin in four medulloblastoma cell lines, and ezrin was primarily localized to filopodia. Ezrin-specific small interfering RNA suppressed the formation of filopodia and in vitro migration, invasion, and adhesion. We also used a stably transfected medulloblastoma cell line to study the effect of ezrin overexpression. We showed that high expression of ezrin promotes filopodia formation and in vitro invasion. Finally, athymic mice implanted with ezrin-overexpressing DAOY medullo-blastoma cell clones in the cerebellum showed shortened survival compared with controls. These findings suggest that, in addition to other cytoskeletal proteins, ezrin plays an important role in medulloblastoma adhesion, migration, and invasion.

Regulatory T cells and the PD-L1/PD-1 pathway mediate immune suppression in malignant human brain tumors

Thu, 06 Aug 2009 14:33:30 PDT

The brain is a specialized immune site representing a unique tumor microenvironment. The availability of fresh brain tumor material for ex vivo analysis is often limited because large parts of many brain tumors are resected using ultrasonic aspiration. We analyzed ultrasonic tumor aspirates as a biosource to study immune suppressive mechanisms in 83 human brain tumors. Lymphocyte infiltrates in brain tumor tissues and ultrasonic aspirates were comparable with respect to lymphocyte content and viability. Applying ultrasonic aspirates, we detected massive infiltration of CD4⁺FoxP3⁺CD25^high CD127^low regulatory T cells (Tregs) in glioblastomas (n = 29) and metastatic brain tumors (n = 20). No Treg accumulation was observed in benign tumors such as meningiomas (n = 10) and pituitary adenomas (n = 5). A significant Treg increase in blood was seen only in patients with metastatic brain tumors. Tregs in high-grade tumors exhibited an activated phenotype as indicated by decreased proliferation and elevated CTLA-4 and FoxP3 expression relative to blood Tregs. Functional analysis showed that the tumor-derived Tregs efficiently suppressed cytokine secretion and proliferation of autologous intratumoral lymphocytes. Most tumor-infiltrating Tregs were localized in close proximity to effector T cells, as visualized by immunohistochemistry. Furthermore, 61% of the malignant brain tumors expressed programmed death ligand-1 (PD-L1), while the inhibitory PD-1 receptor was expressed on CD4⁺ effector cells present in 26% of tumors. In conclusion, using ultrasonic tumor aspirates as a biosource we identified Tregs and the PD-L1/PD-1 pathway as immune suppressive mechanisms in malignant but not benign human brain tumors.

Age-incidence patterns of primary CNS tumors in children, adolescents, and adults in England

Thu, 06 Aug 2009 14:33:30 PDT

Around 25% of all tumors in those 0–14 years of age and 9% in those 15–24 years of age involve the CNS. They are the most common cause of cancer-related deaths in both age groups. In adults 25–84 years of age, the proportion of CNS tumors is 2%; 5-year overall survival is 10%–15%; and survivors have considerable morbidity. Comprehensive up-to-date population-based incidence data on these tumors are lacking. We present incidence rates for primary CNS tumors based on data derived from the high-quality national cancer registration system in England. A total of 54,336 CNS tumors of malignant, benign, and uncertain behavior were registered across the whole of England from 1995 through 2003. The age-standardized rates for all ages (0–84 years) was 9.21 per 100,000 person-years. This is higher than previously reported for England because it includes nonmalignant CNS tumors and hence gives a more accurate picture of burden of disease. The age-standardized rates for those 0–14 years of age, 15–24 years of age, and 25–84 years of age were 3.56, 3.26, and 14.57 per 100,000 person-years, respectively. In this article, we describe the changing patterns in the epidemiology of primary CNS tumors in these three age groups with respect to sex, tumor behavior, and histology using the current WHO classification. This information will provide a reference for future studies nationally and internationally and make comparisons relevant and meaningful.

Epigenetic silencing of the kinase tumor suppressor WNK2 is tumor-type and tumor-grade specific

Thu, 06 Aug 2009 14:33:30 PDT

Both genetic and epigenetic mechanisms contribute to meningioma development by altering gene expression and protein function. To determine the relative contribution of each mechanism to meningioma development, we used an integrative approach measuring copy number and DNA methylation changes genomewide. We found that genetic alterations affected 1.9%, 7.4%, and 13.3% of the 691 loci studied, whereas epigenetic mechanisms affected 5.4%, 9.9%, and 10.3% of these loci in grade I, II, and III meningiomas, respectively. Genetic and epigenetic mechanisms rarely involved the same locus in any given tumor. The predilection for epigenetic rather than genetic silencing was exemplified at the 5' CpG island of WNK2, a serine-threonine kinase gene on chromosome 9q22.31. WNK2 is known to negatively regulate epidermal growth factor receptor signaling via inhibition of MEK1 (mitogen-activated protein kinase kinase 1), and point mutations have been reported in WNK1, WNK2, WNK3, and WNK4. In meningiomas, WNK2 was aberrantly methylated in 83% and 71% of grade II and III meningiomas, respectively, but rarely in a total of 209 tumors from 13 other tumor types. Aberrant methylation of the CpG island was associated with decreased expression in primary tumors. WNK2 could be reactivated with a methylation inhibitor in IOMM-Lee, a meningioma cell line with a densely methylated WNK2 CpG island and lack of WNK2 expression. Expression of exogenous WNK2 inhibited colony formation, implicating it as a potential cell growth suppressor. These findings indicate that epigenetic mechanisms are common across meningiomas of all grades and that for specific genes such as WNK2, epigenetic alteration may be the dominant, grade-specific mechanism of gene inactivation.

First report on a prospective trial with yttrium-90-labeled ibritumomab tiuxetan (Zevalin) in primary CNS lymphoma

Maza, S., Kiewe, P., Munz, D. L., Korfel, A., Hamm, B., Jahnke, K., Thiel, E. — Thu, 06 Aug 2009 14:33:30 PDT

Most patients with primary CNS lymphoma (PCNSL) relapse after primary therapy. Standard salvage treatment has not yet been established in PCNSL. Anti-CD20 immunotherapy has expanded treatment options in systemic B-cell lymphoma; however, its use is limited by reconstitution of the blood–brain barrier after tumor shrinkage. The aim of this phase II trial was to evaluate the therapeutic efficacy, toxicity, and biodistribution of yttrium-90 (⁹⁰Y) ibritumomab tiuxetan in PCNSL. Ten patients with relapsed PCNSL were included in a phase II trial and treated with the ⁹⁰Y-labeled anti-CD20 antibody ibritumomab tiuxetan. Nine patients actually received the planned radioimmunotherapy. In six patients, biodistribution of the antibody was measured by indium-111 (¹¹¹In) ibritumomab tiuxetan whole-body scans and single-photon-emission CT (SPECT) of the brain. All patients were evaluated for toxicity and response at least 4 weeks after therapy. Four patients responded: one patient had a complete response lasting 30+ months, and three patients had short-lived responses of <=4 weeks. Five patients progressed, and one patient did not receive treatment due to an infection prior to ⁹⁰Y-antibody administration. Target accumulation of the antibody was demonstrated in four of the six patients examined by SPECT imaging with ¹¹¹In ibritumomab tiuxetan. All patients experienced grade 3/4 hematotoxicity but no acute neurotoxicity. Penetration of a therapeutic antibody into PCNSL and significant clinical activity was shown. Because of limited response duration and considerable hematotoxicity, future investigations should focus on a multimodal approach with additional chemotherapy and preferably autologous stem cell support.

Pseudoprogression in boron neutron capture therapy for malignant gliomas and meningiomas

Thu, 06 Aug 2009 14:33:30 PDT

Pseudoprogression has been recognized and widely accepted in the treatment of malignant gliomas, as transient increases in the volume of the enhanced area just after chemoradiotherapy, especially using temozolomide. We experienced a similar phenomenon in the treatment of malignant gliomas and meningiomas using boron neutron capture therapy (BNCT), a cell-selective form of particle radiation. Here, we introduce representative cases and analyze the pathogenesis. Fifty-two cases of malignant glioma and 13 cases of malignant meningioma who were treated by BNCT were reviewed retrospectively mainly via MR images. Eleven of 52 malignant gliomas and 3 of 13 malignant meningiomas showed transient increases of enhanced volume in MR images within 3 months after BNCT. Among these cases, five patients with glioma underwent surgery because of suspicion of relapse. In histology, most of the specimens showed necrosis with small amounts of residual tumor cells. Ki-67 labeling showed decreased positivity compared with previous samples from the individuals. Fluoride-labeled boronophenylalanine PET was applied in four and two cases of malignant gliomas and meningiomas, respectively, at the time of transient increase of lesions. These PET scans showed decreased lesion:normal brain ratios in all cases compared with scans obtained prior to BNCT. With or without surgery, all lesions were decreased or stable in size during observation. Transient increases in enhanced volume in malignant gliomas and meningiomas immediately after BNCT seemed to be pseudoprogression. This pathogenesis was considered as treatment-related intratumoral necrosis in the subacute phase after BNCT.

Intracranial low-grade gliomas in adults: 30-year experience with long-term follow-up at Mayo Clinic

Thu, 06 Aug 2009 14:33:30 PDT

The purpose of this study was to evaluate long-term survival in patients with nonpilocytic low-grade gliomas (LGGs). Records of 314 adult patients with nonpilocytic LGGs diagnosed between 1960 and 1992 at the Mayo Clinic, Rochester, Minnesota, were retrospectively reviewed. The Kaplan-Meier method estimated progression-free survival (PFS) and overall survival (OS). Median age at diagnosis was 36 years. Median follow-up was 13.6 years. Operative pathology revealed pure astrocytoma in 181 patients (58%), oligoastrocytoma in 99 (31%), and oligodendroglioma in 34 (11%). Gross total resection (GTR) was achieved in 41 patients (13%), radical subtotal resection (rSTR) in 33 (11%), subtotal resection in 130 (41%), and biopsy only in 110 (35%). Median OS was 6.9 years (range, 1 month–38.5 years). Adverse prognostic factors for OS identified by multivariate analysis were tumor size 5 cm or larger, pure astrocytoma histology, Kernohan grade 2, undergoing less than rSTR, and presentation with sensory motor symptoms. Statistically significant adverse prognostic factors for PFS by multivariate analysis were only tumor size 5 cm or larger and undergoing less than rSTR. In patients who underwent less than rSTR, radiotherapy (RT) was associated with improved OS and PFS. A substantial proportion of patients have a good long-term prognosis after GTR and rSTR, with nearly half of patients free of recurrence 10 years after diagnosis. Postoperative RT was associated with improved OS and PFS and is recommended for patients after subtotal resection or biopsy.

Long-term control of disseminated pleomorphic xanthoastrocytoma with anaplastic features by means of stereotactic irradiation

Thu, 06 Aug 2009 14:33:30 PDT

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm of the brain. Some PXAs are accompanied by anaplastic features and are difficult to manage because of frequent recurrences that lead to early death. No previous reports have demonstrated consistent efficacy of adjuvant radiotherapy or chemotherapy for this disease. We report a case of PXA with anaplastic features treated with stereotactic irradiation (STI) that resulted in long-term control of repeatedly recurring nodules throughout the neuraxis. A 47-year-old woman presented with an epileptic seizure due to a large tumor in the right frontal lobe. The tumor was resected and diagnosed as PXA with anaplastic features. Sixteen months later, a relapse at the primary site was noted and treated with stereotactic radiosurgery using Gamma Knife. Two years later, the patient developed a tumor nodule in the cervical spinal cord that histologically corresponded to a small-cell glioma with high cellularity and prominent MIB-1 (mindbomb homolog 1) labeling. In the following months, multiple nodular lesions appeared throughout the CNS, and STI was performed six times for eight intracranial lesions using Gamma Knife and twice using a linear accelerator, for three spinal cord lesions in total. All lesions treated with STI were well controlled, and the patient was free from symptomatic progression for 50 months. However, diffuse dissemination along the craniospinal axis eventually progressed, and she died 66 months after initial diagnosis. Autopsy showed that the nodules remained well demarcated from the surrounding nervous system tissue. STI may be an effective therapeutic tool for controlling nodular dissemination of PXA with anaplastic features.

Identifying Muir-Torre syndrome in a patient with glioblastoma multiforme

Thu, 06 Aug 2009 14:33:30 PDT

Patients with Muir-Torre syndrome, an autosomal-dominant familial tumor condition caused by germline mutation of the DNA mismatch repair genes, MSH2 or MLH1, present with tumors of the sebaceous gland and visceral malignancies characterized by microsatellite instability. Here we show development of glioblastoma multiforme in a patient with Muir-Torre syndrome. Immunohistochemical analysis of the brain tumor and colon cancer revealed loss of the DNA mismatch repair gene detected by the genetic test, suggesting a pathogenic link.

SOCIETY NEWS

Pelloski, C. E. — Thu, 06 Aug 2009 14:33:30 PDT

Quality of Life: A Fertile Field for Inquiry

Yung, W. K. A. — Mon, 08 Jun 2009 07:23:33 PDT

Occupational exposure to magnetic fields and the risk of brain tumors

Mon, 08 Jun 2009 07:23:33 PDT

We investigated the association between occupational exposure to extremely low-frequency magnetic fields (MFs) and the risk of glioma and meningioma. Occupational exposure to MF was assessed for 489 glioma cases, 197 meningioma cases, and 799 controls enrolled in a hospital-based case–control study. Lifetime occupational history questionnaires were administered to all subjects; for 24% of jobs, these were supplemented with job-specific questionnaires, or "job modules," to obtain information on the use of electrically powered tools or equipment at work. Job-specific quantitative estimates for exposure to MF in milligauss were assigned using a previously published job exposure matrix (JEM) with modification based on the job modules. Jobs were categorized as <=1.5 mG, >1.5 to <3.0 mG, and >=3.0 mG. Four exposure metrics were evaluated: (1) maximum exposed job; (2) total years of exposure >1.5 mG; (3) cumulative lifetime exposure; and (4) average lifetime exposure. Odds ratios (ORs) were calculated using unconditional logistic regression with adjustment for the age, gender, and hospital site. The job modules increased the number of jobs with exposure >=3.0 mG from 4% to 7% relative to the JEM. No statistically significant elevation in ORs or trends in ORs across exposure categories was observed using four different exposure metrics for the three tumor types analyzed. Occupational exposure to MFs assessed using job modules was not associated with an increase in the risk for glioma, glioblastoma, or meningioma among the subjects evaluated in this study.

Antitumor effect in medulloblastoma cells by gefitinib: Ectopic HER2 overexpression enhances gefitinib effects in vivo

Mon, 08 Jun 2009 07:23:33 PDT

The effects of the epidermal growth factor receptor (EGFR) inhibitor gefitinib on cell growth and signaling were evaluated in three medulloblastoma (MB) cell lines (D283, D341, Daoy), one supratentorial primitive neuroectodermal tumor cell line (PFSK), and four MB primary cultures. Cell lines showed diverse expression of EGFR and human epidermal receptor 2 (HER2), with high levels of constitutively activated HER2 in the HER2-overexpressing D341 and D283 cells. Gefitinib sensitivity varied across lines and was not related to expression of HER receptors or receptor baseline activation. Gefitinib induced G₀/G₁ arrest in all lines, whereas apoptosis was dose-dependently induced only in D283 and D341 cells. The molecular response to gefitinib was investigated in Daoy and D341 lines, which showed a higher (half-maximal inhibitory concentration [IC₅₀], 3.8 µM) and lower (IC₅₀, 6.6 µM) sensitivity to the agent, respectively. Gefitinib inhibited constitutive and EGF-triggered EGFR phosphorylation in both lines but was ineffective in constitutive activation of HER2 in D341 cells. Phosphorylated AKT inhibition paralleled that of phosphorylated EGFR, suggesting the presence of an autocrine gefitinib-sensitive EGFR/AKT pathway. On the whole, EGF-dependent signaling was less responsive to ligand stimulation and gefitinib inhibition in D341 cells, which correlated with the lower sensitivity to gefitinib's antiproliferative effect of this line. In vivo, the growth of D341 and Daoy xenografts treated with gefitinib at 150 mg/kg per day was inhibited by approximately 50%. Ectopically overexpressed HER2 in Daoy cells significantly increased sensitivity to gefitinib's antitumor effects in vivo (tumor volume inhibition = 78%). Our data indicate that gefitinib might be a molecularly targeted agent for the treatment of MB.

AMPA receptors promote perivascular glioma invasion via {beta}1 integrin-dependent adhesion to the extracellular matrix

Piao, Y., Lu, L., de Groot, J. — Mon, 08 Jun 2009 07:23:33 PDT

High-grade gliomas release excitotoxic concentrations of glutamate, which has been shown to enhance tumor proliferation and migration. -Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) glutamate receptors are abundantly expressed at the invading edge of glioblastoma specimens, suggesting they may play an important biologic role in tumor invasion. In this study, we examined potential mechanisms by which AMPA receptor (AMPAR) expression and stimulation promote glioma cell migration and invasion. Overexpression of GluR1, the most abundant AMPAR subunit in gliomas, positively correlated with glioma cell adhesion to type I and type IV collagen, which was decreased in cells with knockdown of GluR1 and with blocking antibodies to β1 integrin. Furthermore, stimulation of the AMPAR led to detachment of cells from the extracellular matrix (ECM). Immunoprecipitation studies showed that GluR1 associated with the actin cytoskeleton-linked protein band 4.1B (brain type), which may serve as a link between GluR1 and integrins. Overexpression of GluR1 correlated with increased cell-surface expression of β1 integrin, increased phosphorylation of focal adhesion kinase (FAK-Y397), and enhanced numbers of focal adhesion (FA) complexes. Cells overexpressing GluR1 had increased colocalization of actin and paxillin at FAs and, in several glioma cell lines, significantly increased invasion in an in vitro Matrigel transwell assay. Likewise, in an intracranial xenograft model, overexpression of GluR1 led to perivascular and subependymal glioma cell invasion similar to patterns of tumor dissemination described in human glioblastoma. Together, these results suggest that AMPARs may link signals from the ECM to sites of FA, where signal integration promotes tumor invasion.

Pediatric glioblastomas: A histopathological and molecular genetic study

Mon, 08 Jun 2009 07:23:33 PDT

Glioblastoma multiforme (GBM) occurs rarely in children. Relatively few studies have been performed on molecular properties of pediatric GBMs. Our objective in this study was to evaluate the genetic alterations in pediatric GBM (age <= 18 years) with special reference to p53, p16, and p27 protein expression, alterations of the epidermal growth factor receptor (EGFR), and deletion of the phosphate and tensin homolog gene (PTEN). Thirty cases of childhood GBMs reported between January 2002 and June 2007 were selected, and slides stained with hematoxylin and eosin were reviewed. Immunohistochemical staining was performed for EGFR, p53, p16, and p27, and tumor proliferation was assessed by calculating the MIB-1 labeling index (LI). Fluorescence in situ hybridization analysis was performed to evaluate for EGFR amplification and PTEN deletion. Histopathological features and MIB-1 LI were similar to adult GBMs. p53 protein expression was observed in 63%. Although EGFR protein overexpression was noted in 23% of cases, corresponding amplification of the EGFR gene was rare (5.5%). Deletion of the PTEN gene was also equally rare (5.5%). One case showed polysomy (chromosomal gains) of chromosomes 7 and 10. Loss of p16 and p27 immunoexpression was observed in 68% and 54% of cases, respectively. In pediatric de novo/primary GBMs, deletion of PTEN and EGFR amplification are rare, while p53 alterations are more frequent compared to primary adult GBMs. Frequency of loss of p16 and p27 immunoexpression is similar to their adult counterparts. This suggests that pediatric malignant gliomas are distinctly different from adult GBMs, highlighting the need for identification of molecular targets that may be adopted for future novel therapeutic strategies.

Induction of MGMT expression is associated with temozolomide resistance in glioblastoma xenografts

Mon, 08 Jun 2009 07:23:33 PDT

Temozolomide (TMZ)-based therapy is the standard of care for patients with glioblastoma multiforme (GBM), and resistance to this drug in GBM is modulated by the DNA repair protein O⁶-methylguanine-DNA methyltransferase (MGMT). Expression of MGMT is silenced by promoter methylation in approximately half of GBM tumors, and clinical studies have shown that elevated MGMT protein levels or lack of MGMT promoter methylation is associated with TMZ resistance in some, but not all, GBM tumors. In this study, the relationship between MGMT protein expression and tumor response to TMZ was evaluated in four GBM xenograft lines that had been established from patient specimens and maintained by serial subcutaneous passaging in nude mice. Three MGMT unmethylated tumors displayed elevated basal MGMT protein expression, but only two of these were resistant to TMZ therapy (tumors GBM43 and GBM44), while the other (GBM14) displayed a level of TMZ sensitivity that was similar in extent to that seen in a single MGMT hypermethylated line (GBM12). In tissue culture and animal studies, TMZ treatment resulted in robust and prolonged induction of MGMT expression in the resistant GBM43 and GBM44 xenograft lines, while MGMT induction was blunted and abbreviated in GBM14. Consistent with a functional significance of MGMT induction, treatment of GBM43 with a protracted low-dose TMZ regimen was significantly less effective than a shorter high-dose regimen, while survival for GBM14 was improved with the protracted dosing regimen. In conclusion, MGMT expression is dynamically regulated in some MGMT nonmethylated tumors, and in these tumors, protracted dosing regimens may not be effective.

Glutathione S-transferase M1 and T1 polymorphisms may predict adverse effects after therapy in children with medulloblastoma

Mon, 08 Jun 2009 07:23:33 PDT

Glutathione S-transferases (GSTs) are polymorphic enzymes that catalyze the glutathione conjugation of alkylating agents, platinum compounds, and free radicals formed by radiation used to treat medulloblastoma. We hypothesized that GST polymorphisms may be responsible, in part, for individual differences in toxicity and responses in pediatric medulloblastoma. We investigated the relationship between GSTM1 and GSTT1 polymorphisms and survival and toxicity in 42 children with medulloblastoma diagnosed and treated at the Texas Children's Cancer Center. We conducted Kaplan-Meier analyses to determine if the GST polymorphisms were related to progression-free survival (PFS) and performed logistic regression to explore associations between GST polymorphisms and occurrence of grade 3 or greater (>=Gr 3) myelosuppression, ototoxicity, nephrotoxicity, neurotoxicity, and intellectual impairment. Patients with at least one null genotype had a 4.3 (95% confidence interval, 1.1–16.8), 3.7 (1–13.6), and 6.4 (1.2–34) times increased risk for any >=Gr 3 toxicity, any >=Gr 3 toxicity excluding peripheral neuropathy, and any >=Gr 3 toxicity requiring omission or cessation of chemotherapy, respectively. Compared with all others, patients with at least one null genotype had, on average, 27.2 (p x= 0.0002), 29 (p = 0.0004), and 21.7 (p = 0.002) lower full-scale, performance, and verbal intelligence quotient (IQ) scores, respectively. GSTM1 and GSTT1 polymorphisms may predict adverse events, including cognitive impairment after therapy, in patients with medulloblastoma. A larger study to validate these findings is under way.

Differential effect of sunitinib on the distribution of temozolomide in an orthotopic glioma model

Zhou, Q., Gallo, J. M. — Mon, 08 Jun 2009 07:23:33 PDT

Normalization of tumor vasculature by antiangiogenic agents may improve the delivery of cytotoxic drugs to the tumor, leading to more effective therapy. In this study, we used pharmacokinetic and pharmacodynamic approaches to investigate how sunitinib at different dose levels affects brain distribution of temozolomide (TMZ), and to ascertain the relationship between intratumoral TMZ concentrations and tumor vascularity in an orthotopic human glioma model. Three groups of intracerebral U87MG tumor-bearing mice were given either vehicle or sunitinib at 20 mg/kg or 60 mg/kg per day for 7 days before receiving a steady-state regimen of TMZ that consisted of an intravenous bolus and a 3-h intraarterial infusion. TMZ concentrations in plasma, normal brain, and brain tumor were determined, and several biomarkers related to the antiangiogenic activity of sunitinib were examined. TMZ distribution in the normal brain as indicated by the brain-to-plasma steady-state TMZ concentration ratios was analogous across the three treatment groups. The brain tumor-to-plasma steady-state TMZ concentration (ss C_t/C_p) ratio was significantly increased in the 20 mg/kg sunitinib group (0.98 ± 0.17) compared with the control (0.76 ± 0.17) and 60 mg/kg sunitinib (0.68 ± 0.09) groups. The ss C_t/C_p ratios were significantly correlated with the vascular normalization index (VNI), derived from the expression of CD31, collagen IV, and -smooth muscle actin, which represents the fraction of functioning vessels out of the total tumor vessels. In conclusion, the effect of sunitinib on the brain tumor distribution of TMZ was dose dependent and indicated that optimal tumor exposure was achieved at a lower dose and was associated with the VNI.

Incidence of and survival from oligodendroglioma in Denmark, 1943-2002

Nielsen, M. S., Christensen, H. C., Kosteljanetz, M., Johansen, C. — Mon, 08 Jun 2009 07:23:33 PDT

We established the nationwide, population-based incidence of oligodendroglioma in Denmark during 59 years of monitoring and compared the overall survival of patients with oligodendroglial tumors during the periods 1943–1977 and 1978–2002. On the basis of reports in the Danish Cancer Registry, 1,304 cases of oligodendroglioma were included in the study. We calculated sex- and age-specific incidence rates in 5-year age intervals and for 5-year calendar periods. Overall survival was estimated by the Kaplan-Meier method. In the period 1943–2002, the incidence rate of oligodendroglioma was less than 1 case per 100,000 person-years, but varied somewhat when viewed across isolated periods. Comparison of the incidence rate before and after the introduction of CT scanning did not reveal a significant difference in the incidence rate. The median survival increased from 1.4 years (95% confidence interval [CI], 1.0–1.6) to 3.4 years (95% CI, 2.6–4.2) during the period of study. The overall incidence of oligodendroglioma showed a relatively stable pattern over nearly 60 years of monitoring. Overall survival improved significantly during the study period, which could partly be due to improved diagnostic methods and treatment options.

Racial differences in primary central nervous system lymphoma incidence and survival rates

Mon, 08 Jun 2009 07:23:33 PDT

To determine racial and ethnic differences in incidence and survival in patients with primary central nervous system lymphoma (PCNSL), NCI Surveillance, Epidemiology, and End Results (SEER) program data from 1992 to 2002 were queried. Data were substratified by age (20–49 years vs. 50 or above) and race (White, Black, Asian/Pacific Islander [A/PI], American Indian/Alaskan Native [AI/AN]). Incidence of PCNSL and survival were calculated by SEER^*Stat software. The incidence rates were 0.94 per 100,000 per year (95% confidence interval [CI] 0.90–0.98) for Whites, 1.10 (95% CI 0.98–1.22) for Blacks, 0.51 (95% CI 0.28–0.74) for AI/AN, and 0.64 (95% CI 0.56–0.72) for A/PI. In patients aged 20–49 years the rates were 0.72 (95% CI 0.68–0.76) for Whites, 1.43 (95% CI 1.27–1.59) for Blacks, 0.58 (95% CI 0.30–0.86) for AI/AN, and 0.21 (CI 0.15–0.27) for A/PI. In patients over 49 years, the rates were 1.30 (95% CI 1.22–1.38) for Whites, 0.56 (95% CI 0.40–0.72) for Blacks, 0.34 (95% CI 0–0.70) for AI/AN, and 1.31 (95% CI 1.00–1.53) for A/PI. PCNSL incidence for ages 20–49 years for Black patients was twice that for Whites. Incidence for ages over 49 years for Whites was twice that for Blacks. Survival at 12 months, 24 months, and 60 months was higher among Whites than Blacks. Research is needed to determine the origin of these differences.

Pediatric giant cell glioblastoma: New insights into a rare tumor entity

Mon, 08 Jun 2009 07:23:33 PDT

Little is known about giant cell glioblastoma (GCG) in pediatric patients. The present study identified 18 pediatric patients with centrally reviewed GCG from the HIT-GBM database of the Gesellschaft für Paediatrische Onkologie und Haematologie in Germany, Austria, and Switzerland. Clinical and epidemiological data were compared with those of 178 pediatric patients with centrally reviewed glioblastoma multiforme (GBM) from the same database. In this unique series, median age, male preference, and median clinical history did not differ significantly between pediatric GCG and GBM patients. GCG showed a stronger predilection for cerebral hemispheres than did GBM, which may only partly explain the higher percentage of gross total tumor resections in GCG patients. Most surprising, the widely distributed hypothesis that GCG may imply a better prognosis than GBM could not be substantiated for our pediatric series. Future studies with larger patient numbers and molecular pathological analyses are still needed to corroborate the present findings and further elucidate the biology of GCG in children.

Quality of life in adults with brain tumors: Current knowledge and future directions

Liu, R., Page, M., Solheim, K., Fox, S., Chang, S. M. — Mon, 08 Jun 2009 07:23:33 PDT

Quality of life is an important area of clinical neurooncology that is increasingly relevant as survivorship increases and as patients experience potential morbidities associated with new therapies. This review of quality-of-life studies in the brain tumor population aims to summarize what is currently known about quality of life in patients with both low-grade and high-grade tumors and suggest how we may use this knowledge to direct future research. To date, reports on quality of life have been primarily qualitative and focused on specific symptoms such as fatigue, sleep disorders, and cognitive dysfunction, as well as some symptom clusters. However, the increasing interest in exploring quality of life as a primary end point for cancer therapy has established a need for prospective, controlled studies to assess baseline and serial quality-of-life parameters in brain tumor patients in order to plan and evaluate appropriate and timely interventions for their symptoms.

SOCIETY NEWS

Pelloski, C. E. — Mon, 08 Jun 2009 07:23:33 PDT

Stem Cells for Treating Glioblastoma: How Close to Reality?

James, C. D., Cavenee, W. K. — Tue, 31 Mar 2009 11:32:15 PDT

In vivo gene delivery by embryonic-stem-cell-derived astrocytes for malignant gliomas

Uzzaman, M., Keller, G., Germano, I. M. — Tue, 31 Mar 2009 11:32:15 PDT

The treatment of malignant gliomas with current therapies remains a challenge in neurooncology. Our recent work showed that embryonic stem cell (ESC)-derived astrocytes conditionally expressing genes can be used to induce apoptosis in malignant glioma cells in vitro. The tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) gene has been shown to induce apoptosis in a variety of tumor cells, including gliomas. The aim of this study was to assess the proapoptotic effects of transgenic TRAIL delivered by ESC-derived astrocytes on malignant gliomas in vivo. Malignant glioma A172 cells were used to induce heterotopic xenografts in nude mice. ESC-derived astrocytes conditionally expressing TRAIL were injected into the xenografts. TRAIL expression was documented in the malignant glioma xenografts by reverse transcription PCR and immunohistochemistry after external gene induction. A significant reduction in tumor volume occurred 48 h after a single injection (14%) and double injections (31%) in the experimental groups. Terminal dUTP nick end labeling (TUNEL) revealed abundant apoptotic tumor cells in the experimental groups. Seven days after injection, the tumor had undergone severe necrosis, with only scattered residual tumor cells at the periphery. Death receptor DR4 expression increased significantly in the experimental groups compared with controls. Our data suggest that ESC-derived astrocytes conditionally expressing TRAIL should be considered as vectors to deliver gene therapy for malignant gliomas.

Efficacy of the HSP90 inhibitor 17-AAG in human glioma cell lines and tumorigenic glioma stem cells

Tue, 31 Mar 2009 11:32:15 PDT

Glioblastoma multiforme (GBM) arises from genetic and signaling abnormalities in components of signal transduction pathways involved in proliferation, survival, and the cell cycle axis. Studies to date with single-agent targeted molecular therapy have revealed only modest effects in attenuating the growth of these tumors, suggesting that targeting multiple aberrant pathways may be more beneficial. Heat-shock protein 90 (HSP90) is a molecular chaperone that is involved in the conformational maturation of a defined group of client proteins, many of which are deregulated in GBM. 17-allylamino-17-demethoxygeldanamycin (17-AAG) is a well-characterized HSP90 inhibitor that should be able to target many of the aberrant signal transduction pathways in GBM. We assessed the ability of 17-AAG to inhibit the growth of glioma cell lines and glioma stem cells both in vitro and in vivo and assessed its ability to synergize with radiation and/or temozolomide, the standard therapies for GBM. Our results reveal that 17-AAG is able to inhibit the growth of both human glioma cell lines and glioma stem cells in vitro and is able to target the appropriate proteins within these cells. In addition, 17-AAG can inhibit the growth of intracranial tumors and can synergize with radiation both in tissue culture and in intracranial tumors. This compound was not found to synergize with temozolomide in any of our models of gliomas. Our results suggest that HSP90 inhibitors like 17-AAG may have therapeutic potential in GBM, either as a single agent or in combination with radiation.

Quercetin promotes degradation of survivin and thereby enhances death-receptor-mediated apoptosis in glioma cells

Siegelin, M. D., Reuss, D. E., Habel, A., Rami, A., von Deimling, A. — Tue, 31 Mar 2009 11:32:15 PDT

The flavonoid quercetin has been reported to inhibit the proliferation of cancer cells, whereas it has no effect on nonneoplastic cells. U87-MG, U251, A172, LN229, and U373 malignant glioma cells were treated with quercetin (50–200 µM). Quercetin did not cause cytotoxicity 24 h after treatment. Combining quercetin with tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) strongly augmented TRAIL-mediated apoptosis in U87-MG, U251, A172, and LN229 glioma cells; U373 cells could not be sensitized by quercetin to TRAIL-mediated apoptosis. TRAIL-induced apoptosis was enhanced by quercetin-induced reduction of survivin protein levels. Upon treatment with quercetin, the protein level of survivin was strongly suppressed in U87-MG, U251, and A172 but not in U373 glioma cells. Quercetin exposure resulted in proteasomal degradation of survivin. TRAIL-quercetin–induced apoptosis was markedly reduced by overexpression of survivin. In addition, upon treatment with quercetin, downregulation of survivin was also regulated by the Akt pathway. Taken together, the results of the present study suggest that quercetin sensitizes glioma cells to death-receptor–mediated apoptosis by suppression of inhibitor of the apoptosis protein survivin.

Promyelocytic leukemia protein induces apoptosis due to caspase-8 activation via the repression of NF{kappa}B activation in glioblastoma

Tue, 31 Mar 2009 11:32:15 PDT

Promyelocytic leukemia (PML) protein plays an essential role in the induction of apoptosis; its expression is reduced in various cancers. As the functional roles of PML in glioblastoma multiforme (GBM) have not been clarified, we assessed the expression of PML protein in GBM tissues and explored the mechanisms of PML-regulated cell death in GBM cells. We examined the PML mRNA level and the expression of PML protein in surgical GBM specimens. PML-regulated apoptotic mechanisms in GBM cells transfected with plasmids expressing the PML gene were examined. The protein expression of PML was significantly lower in GBM than in non-neoplastic tissues; approximately 10% of GBM tissues were PML-null. The PML mRNA levels were similar in both tissue types. The overexpression of PML activated caspase-8 and induced apoptosis in GBM cells. In these cells, PML decreased the expression of transactivated forms of NFB/p65, and c-FLIP gene expression was suppressed. Therefore, PML-induced apoptosis resulted from the suppression of the transcriptional activity of NFB/p65. PML overexpression decreased phosphorylated IB and nuclear NFB/p65 and increased the expression of the suppressor of cytokine signaling (SOCS-1). A proteasome inhibitor blocked the reduction of activated p65 by PML. The reduction of PML is associated with the pathogenesis of GBM. PML induces caspase-8–dependent apoptosis via the repression of NFB activation by which PML facilitates the proteasomal degradation of activated p65 and the sequestration of p65 with IB in the cytoplasm. This novel mechanism of PML-regulated apoptosis may represent a therapeutic target for GBM.

Bevacizumab and carboplatin increase survival and asymptomatic tumor volume in a glioma model

Tue, 31 Mar 2009 11:32:15 PDT

To evaluate efficacy and MRI findings after intravenous bevacizumab and/or carboplatin in a human glioma animal model, we randomized male nude rats with intracerebral UW28 human glioma xenografts to four groups: (1) controls (n = 9), (2) bevacizumab 10 mg/kg (n = 6), (3) carboplatin 200 mg/m² (n = 6), and (4) bevacizumab + carboplatin (n = 6). MRI was performed on the day of treatment (day 7–10) and 1 week later, and rats were followed for survival. Dynamic MRI was done in three controls and three rats treated with bevacizumab with or without carboplatin before and 24 h after treatment. Median overall survival (OS) was as follows: group 1, 16 days; group 2, 23 days; group 3, 22 days; group 4, 36 days. OS was significantly longer in group 4 than in group 1 (p = 0.0011), group 2 (p = 0.0014), and group 3 (p = 0.0015), and rats had significantly larger tumors. No objective tumor responses were observed on MR images at 1 week after treatment; however, after bevacizumab, dynamic MRI showed reduced gadolinium enhancement intensity and increased time to peak, consistent with decreased vascular permeability. Carboplatin + bevacizumab is effective and superior over bevacizumab or carboplatin monotherapy in this animal model. Increased survival concomitant with increased asymptomatic tumor volume is suggestive that vascular targeting with reduced peritumoral edema and mass effect contributes to the efficacy of bevacizumab. The promising survival data warrant future clinical trials using bevacizumab + carboplatin.

Therapeutic efficacy of a polymeric micellar doxorubicin infused by convection-enhanced delivery against intracranial 9L brain tumor models

Tue, 31 Mar 2009 11:32:15 PDT

Convection-enhanced delivery (CED) with various drug carrier systems has recently emerged as a novel chemotherapeutic method to overcome the problems of current chemotherapies against brain tumors. Polymeric micelle systems have exhibited dramatically higher in vivo antitumor activity in systemic administration. This study investigated the effectiveness of CED with polymeric micellar doxorubicin (DOX) in a 9L syngeneic rat model. Distribution, toxicity, and efficacy of free, liposomal, and micellar DOX infused by CED were evaluated. Micellar DOX achieved much wider distribution in brain tumor tissue and surrounding normal brain tissue than free DOX. Tissue toxicity increased at higher doses, but rats treated with micellar DOX showed no abnormal neurological symptoms at any dose tested (0.1–1.0 mg/ml). Micellar DOX infused by CED resulted in prolonged median survival (36 days) compared with free DOX (19.6 days; p = 0.0173) and liposomal DOX (16.6 days; p = 0.0007) at the same dose (0.2 mg/ml). This study indicates the potential of CED with the polymeric micelle drug carrier system for the treatment of brain tumors.

Sagopilone crosses the blood-brain barrier in vivo to inhibit brain tumor growth and metastases

Tue, 31 Mar 2009 11:32:15 PDT

The aim of this study was to determine the efficacy of sagopilone (ZK-EPO), a novel epothilone, compared with other anticancer agents in orthotopic models of human primary and secondary brain tumors. Autoradiography and pharmacokinetic analyses were performed on rats and mice to determine passage across the blood–brain barrier and organ distribution of sagopilone. Mice bearing intracerebral human tumors (U373 or U87 glioblastoma, MDA-MB-435 melanoma, or patient-derived non-small-cell lung cancer [NSCLC]) were treated with sagopilone 5–10 mg/kg, paclitaxel 8–12.5 mg/kg (or temozolomide, 100 mg/kg) or control (vehicle only). Tumor volume was measured to assess antitumor activity. Sagopilone crossed the blood–brain barrier in both rat and mouse models, leading to therapeutically relevant concentrations in the brain with a long half-life. Sagopilone exhibited significant antitumor activity in both the U373 and U87 models of human glioblastoma, while paclitaxel showed a limited effect in the U373 model. Sagopilone significantly inhibited the growth of tumors from CNS metastasis models (MDA-MB-435 melanoma and patient-derived Lu7187 and Lu7466 NSCLC) implanted in the brains of nude mice, in contrast to paclitaxel or temozolomide. Sagopilone has free access to the brain. Sagopilone demonstrated significant antitumor activity in orthotopic models of both glioblastoma and CNS metastases compared with paclitaxel or temozolomide, underlining the value of further research evaluating sagopilone in the treatment of brain tumors. Sagopilone is currently being investigated in a broad phase II clinical trial program, including patients with glioblastoma, NSCLC, breast cancer, and melanoma.

Phase II trial of preirradiation and concurrent temozolomide in patients with newly diagnosed anaplastic oligodendrogliomas and mixed anaplastic oligoastrocytomas: RTOG BR0131

Tue, 31 Mar 2009 11:32:15 PDT

The primary objectives of this phase II study were to evaluate the use of preirradiation temozolomide followed by concurrent temozolomide and radiotherapy (RT) in patients with newly diagnosed anaplastic oligodendroglioma (AO) and mixed anaplastic oligoastrocytoma (MOA). Preirradiation temozolomide (150 mg/m²/day) was given on a 7-day-on/7-day-off schedule for up to six cycles. The primary end point was the response rate during the 6-month, pre-RT chemotherapy. Tumor tissue was analyzed for the presence of chromosomal deletions on 1p and 19q and for MGMT-promoter methylation. Forty-two patients were enrolled; 39 were eligible. The objective response rate was 32% (6% [complete response, CR], 26% [partial response PR]), and the rate of progression during pre-RT chemotherapy was 10%. The worst nonhematological toxicity was grade 4 in three patients (8%). Twenty-two patients completed concurrent chemotherapy and RT. There were no grade 4 nonhematological toxicities during the concurrent chemotherapy and RT. Seventeen of 28 (60.7%) evaluable cases had codeletion of 1p/19q; all 17 were free from progression at 6 months. Sixteen of 20 (80%) evaluable cases had MGMT-promoter methylation; all 16 were free from progression at 6 months. In conclusion, the rate of progression of 10% during pre-RT temozolomide chemotherapy for newly diagnosed AO and MAO compared favorably with prior experience with pre-RT PCV chemotherapy (20% in RTOG 9402). The toxicity of the dose-intense pre-RT regimen used in this study may warrant evaluation of other, less intense dosing strategies. Future studies will need to prospectively stratify patients according to the presence of deletions of chromosomes 1p and 19q.

Prognostic significance of imaging contrast enhancement for WHO grade II gliomas

Tue, 31 Mar 2009 11:32:15 PDT

In this study, we investigated the prognostic value of MRI contrast enhancement (CE) at the time of histological diagnosis specifically in a selected population of WHO grade II gliomas. We reviewed 927 histologically proven WHO grade II gliomas for which contrast-enhanced MR images were available at the time of histological diagnosis. CE patterns were classified into three categories: "patchy and faint," "nodular-like," and "ring-like." CE progression over time was recorded before oncological treatment on successive MR images, when available. CE was present in 143 cases (15.9%), with 93 patchy and faint, 50 nodular-like, and no ring-like patterns. CE areas were time progressive before oncological treatment in 35 of the 56 available cases (62.5%). Regardless of its pattern, the presence of CE was not significantly associated with a worsened prognosis (p = 0.415) by univariate analysis. Only the nodular-like pattern of CE (p < 0.01) and the time-progressive CE (p < 0.001) in the available subgroup proved to be statistically associated with survival since first oncological treatment. The present results show the necessity, in cases of WHO grade II gliomas, to study CE at the time of histological diagnosis and, whenever possible, to follow its progression over time before oncological treatment. Nodular-like CE and time-progressive CE are associated with a worsened prognosis, both suggesting malignant transformation, even though histopathological examination cannot initially disclose signs of malignancy in those areas.

Adult gliosarcoma: epidemiology, natural history, and factors associated with outcome

Kozak, K. R., Mahadevan, A., Moody, J. S. — Tue, 31 Mar 2009 11:32:15 PDT

The epidemiology and natural history of adult gliosarcomas (GSMs), as well as patient and treatment factors associated with outcome, are ill defined. Patients over 20 years of age with GSM diagnosed from 1988 to 2004 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier survival analysis and Cox models were used to examine outcomes. Similar analyses were conducted for patients diagnosed with glioblastoma (GBM) over the same time period. GSM represented 2.2% of the 16,388 patients identified with either GSM or GBM. No significant differences between GSM and GBM were identified with respect to age, gender, race, tumor size, or use of adjuvant radiation therapy (RT). Patients with GSM were more likely to have temporal lobe involvement and undergo some form of tumor resection. The most important analyzed factors influencing GSM overall survival were age, extent of resection, and use of adjuvant RT. After adjusting for factors impacting overall survival, the prognosis for GSM appears slightly worse than for GBM (HR = 1.17, 95% CI, 1.05–1.31). GSM is a rare malignancy that presents very similarly to GBM with a slightly greater propensity for temporal lobe involvement. Optimal treatment remains to be defined. However, these retrospective findings suggest tumor excision, as opposed to biopsy only, and adjuvant RT may improve outcome. Despite therapy, prognosis remains dismal and outcomes may be inferior to those seen in GBM patients.

Presence of 1q gain and absence of 7p gain are new predictors of local or metastatic relapse in localized resectable neuroblastoma

Tue, 31 Mar 2009 11:32:15 PDT

We have addressed the search of novel genetic prognostic markers in a selected cohort of patients with stroma-poor localized resectable neuroblastoma (NB) who underwent relapse or progression (group 1) or complete remission (group 2) over a minimum follow-up of 32 months from diagnosis. Twenty-three Italian patients with localized resectable NB (stages 1 and 2) diagnosed from 1994 through 2005 were studied. All patients received surgical treatment. Chemotherapy was administered only to the three stage 2 patients who had MYCN-amplified tumors. High-resolution array-comparative genomic hybridization (CGH) DNA copy-number analysis technology was used to identify novel prognostic markers. Chromosome 1p36.22p36.32 loss and 1q22qter gain, detected almost exclusively in group 1 patients, were significantly associated with poor event-free survival (EFS) (p = 0.0024 and p = 0.024, respectively). In contrast, patients with 7p11.2p22 gain, who belonged predominantly to group 2, had a significantly better EFS (p = 0.015). The frequency of 17q gain or 3p and 11q losses did not differ significantly in group 1 versus group 2 NBs. The sensitive technique allowed us to define the smallest region of 1p deletion. In conclusion, 1q22qter gain and 7p11.2p22 gain might represent new prognostic markers in localized resectable NB, but the small study size and the retrospective nature of the findings warrant further validation of the results in larger studies.

Treatment of early childhood medulloblastoma by postoperative chemotherapy and deferred radiotherapy

Tue, 31 Mar 2009 11:32:15 PDT

To investigate the utility of postoperative chemotherapy in delaying radiotherapy and to identify prognostic factors in early childhood medulloblastoma, we studied children younger than 3 years of age registered to the HIT-SKK'87 (Therapieprotokoll für Säuglinge und Kleinkinder mit Hirntumoren [Brain Tumor Radiotherapy for Infants and Toddlers with Medulloblastoma] 1987) trial who received systemic interval chemotherapy until craniospinal radiotherapy was applied at 3 years of age or at relapse, from 1987 to 1993. Children with postoperative residual tumor or metastatic disease received systemic induction chemotherapy prior to interval chemotherapy. Twenty-nine children were eligible for analyses (median age, 1.7 years; median follow-up, 12.6 years). In children without macroscopic metastases, rates (±SEM) for 10-year progression-free survival (PFS) and overall survival (OS) were 52.9% ± 12.1% and 58.8% ± 11.9% (complete resection), and 55.6% ± 16.6% and 66.7% ± 15.7% (incomplete resection), compared with 0% and 0% in children with macroscopic metastases. Survival was superior in nine children with desmoplastic or extensive nodular histology compared with 20 children with classic medulloblastoma (10-year PFS, 88.9% ± 10.5% and 30.0% ± 10.3%, p = 0.003; OS, 88.9% ± 10.5% and 40.0% ± 11.0%, p = 0.006). Eleven of 12 children with tumor progression during chemotherapy had classic medulloblastoma. After treatment, IQ scores were inferior compared with nonirradiated children from the subsequent study, HIT-SKK'92. Classic histology, metastatic disease, and male gender were independent adverse risk factors for PFS and OS in 72 children from HIT-SKK'87 and HIT-SKK'92 combined. In terms of survival, craniospinal radiotherapy was successfully delayed especially in young children with medulloblastoma of desmoplastic/extensive nodular histology, which was a strong independent favorable prognostic factor. Because of the neurocognitive deficits of survivors, the emerging concepts to avoid craniospinal radiotherapy should rely on the histological medulloblastoma subtype.

High-dose methotrexate for elderly patients with primary CNS lymphoma

Tue, 31 Mar 2009 11:32:16 PDT

The introduction of methotrexate (MTX)-based chemotherapy has improved median survival for patients with primary CNS lymphoma (PCNSL). Older age is a negative prognostic marker in patients with PCNSL and may increase the likelihood of MTX toxicity. We studied the response and adverse effects of intravenous high-dose MTX in patients who were 70 or more years of age at the time of diagnosis. We identified 31 patients at our institution diagnosed with PCNSL at age >=70 years (median, 74 years) who were treated with high-dose MTX (3.5–8 g/m²) as initial therapy from 1992 through 2006. The best response to MTX was determined by contrast-enhanced MRI. Toxicity was analyzed by chart review. These 31 patients received a total of 303 cycles of MTX (median, eight cycles per patient). Overall, 87.9% of the cycles required dose reduction because of impaired creatinine clearance. In 30 evaluable patients, the overall radiographic response rate was 96.7%, with 18 complete responses (60%) and 11 partial responses (36.7%). Progression-free survival and overall survival were 7.1 months and 37 months, respectively. Grade I–IV toxicities were observed in 27 of 31 patients and included gastrointestinal disturbances in 58% (3.2% grade III), hematological complications in 80.6% (6.5% grade III), and renal toxicity in 29% (0% grade III/IV). High-dose MTX is associated with a high proportion of radiographic responses and a low proportion of grade III/IV toxicity in patients 70 or more years of age. High-dose MTX should be considered as a feasible treatment option in elderly patients with PCNSL.

Abstracts from the 17th International Conference on Brain Tumor Research and Therapy June 9-12, 2008 Tokyo, Japan

Tue, 31 Mar 2009 11:32:16 PDT

LETTER TO THE EDITOR

Roesler, R., Schroder, N., Schwartsmann, G. — Tue, 31 Mar 2009 11:32:16 PDT

SOCIETY NEWS

Pelloski, C. E. — Tue, 31 Mar 2009 11:32:16 PDT