Prognosis Of Malignant Gliomas Research Articles

Significant role of PPP3CB in malignant gliomas development, prognosis and potential therapeutic application—a study based on comprehensive bioinformatics, cell experiments and immunohistochemistry analyses

IntroductionMalignant gliomas are the most prevalent and fatal types of primary malignant brain tumors with poor prognosis. Protein phosphatase 3 catalytic subunit beta (PPP3CB) is a pivotal constituent of the Ca2+/calmodulin-dependent serine/threonine protein phosphatases and widely expressed in brain. We aimed at identifying whether PPP3CB has potential in being a novel biomarker of malignant gliomas, bringing new insights to clinical management and therapy. MethodsTranscriptomes and clinical data of Glioblastoma (GBM) and low-grade glioma (LGG) samples were downloaded from TCGA and CGGA. We first explored the expressional and survival features of tumor tissues. Then, PPP3CB-associated genes were identified and their functional pathways were explored through GSEA analyses. Western blotting was conducted to modify PPP3CB expression. Samples of glioma patients and healthy controls were collected and immunohistochemistry (IHC) staining was performed to detect protein level. Further, we carried out an immune infiltration analysis, explored the correlation between PPP3CB and immune checkpoint genes, as well as to assessed the tumor mutation burden (TMB) and tumor microenvironment score (TMEscore) of PPP3CB. ResultsPPP3CB expression in malignant glioma tissues was significantly downregulated and was considered an independent prognostic factor. Several functional pathways were observed through functional pathway analyses. PPP3CB's expression was strongly related to the infiltration of various immune cells and expression of key immune checkpoint genes. PPP3CB expression in high-grade gliomas was significantly lower, affecting glioma cells' proliferation and apoptosis in vitro. ConclusionPPP3CB was a potential biomarker for the diagnosis and prognosis of malignant gliomas.

Nuclear translocation of cGAS orchestrates VEGF-A-mediated angiogenesis

Cyclic GMP-AMP synthase (cGAS) senses cytosolic incoming DNA and consequently activates stimulator of interferon response cGAMP interactor 1 (STING) to mount immune response. Here, we show nuclear cGAS could regulate VEGF-A-mediated angiogenesis in an immune-independent manner. We found VEGF-A stimulation induces cGAS nuclear translocation via importin-β pathway. Moreover, nuclear cGAS subsequently regulates miR-212-5p-ARPC3 cascade to modulate VEGF-A-mediated angiogenesis through affecting cytoskeletal dynamics and VEGFR2 trafficking from trans-Golgi network (TGN) to plasma membrane via a regulatory feedback loop. In contrast, cGAS deficiency remarkably impairs VEGF-A-mediated angiogenesis invivo and invitro. Furthermore, we found strong association between the expression of nuclear cGAS and VEGF-A, and the malignancy and prognosis in malignant glioma, suggesting that nuclear cGAS might play important roles in human pathology. Collectively, our findings illustrated the function of cGAS in angiogenesis other than immune surveillance, which might be a potential therapeutic target for pathological angiogenesis-related diseases.

Chaperone protein P4HB predicts temozolomide response and prognosis in malignant glioma

Prolyl 4-hydroxylase beta polypeptide (P4HB) is a chaperone protein associated with temozolomide (TMZ) resistance through the unfolded protein response. Cancer cells with constitutive activation of endoplasmic reticulum stress and upregulation of P4HB have been observed to show resistance against chemotherapies. The present study focused on the evaluation of the prognostic value of P4HB in subtypes of glioma with or without O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. P4HB expression was assessed by immunohistochemical staining in 73 grade I-IV gliomas and its association with the clinicopathological data was determined. It was indicated that P4HB expression was significantly associated with several parameters, including age, tumour grade and the number of TMZ treatment cycles received. In the Kaplan-Meier analysis, P4HB expression was positively associated with risk of mortality and disease progression. In patients treated with TMZ, high P4HB expression was significantly associated with poor overall survival (OS) and progression-free survival (PFS). The association between MGMT promoter methylation and P4HB expression was also assessed. Patients with MGMTMethP4HBLow tumours had the most favourable PFS (48 months) among cases with various combinations of MGMT methylation status and P4HB expression. Multivariate analysis revealed that P4HB may be used as an independent prognostic indicator of OS, particularly in high-grade gliomas. The present study uncovered the potential role of P4HB in a nuanced pathological stratification during clinical decision-making with respect to MGMT promoter methylation status and TMZ treatment.

T11TS repress gliomagenic apoptosis of bone marrow hematopoietic stem cells.

Combating gliomagenic global immunosuppression is one of the emerging key for improving prognosis in malignant glioma. Apoptosis plays a pivotal role within the adult hematopoietic system particularly in regulating the cells of immune system. Gliomagenic regulation of apoptotic mediators within bone marrow milieu has not been elucidated. We previously demonstrated that administration of membrane glycopeptides T11 target structure (T11TS) not only rejuvenate bone marrow hematopoietic stem cells (BMHSCs) from glioma mediated hibernation by inhibiting gliomagenic overexpression of Ang-1/Tie-2 but also stimulate glioma mediated diminution of expression CD34, c-kit, and Sca-1 markers. In the present study, we investigated the impact of glioma on apoptotic signaling cascades of BMHSCs and consequences following T11TS therapy. Bone marrow smear and Annexin V staining confirm gliomagenic acceleration of apoptotic fate of BMHSCs whereas T11TS treatment in glioma-bearing rats disrupted apoptosis of BMHSCs. Flowcytometry, immunoblotting, and immunofluorescence imagining results revealed multi potent T11TS not only significantly downregulates gliomagenic overexpression of Fas, Fas L, Bid, and caspase-8, the pro-apoptotic extrinsic mediators but also strongly inhibits cytosolic release of cytochrome-c, Apf-1, and Bax to deactivate gliomagenic caspase-9, 3 the key intrinsic apoptotic mediators followed by up modulation of anti-apoptotic Bcl-2 in glioma associated HSCs. T11TS is also able to diminish the perforin-granzyme B mediated apoptotic verdict of BMHSCs during gliomagenesis. The anti-apoptotic action of T11TS on glioma associated BMHSCs provide a crucial insight into how T11TS exerts its immunomodulatory action against glioma mediated immune devastation.

Overexpression of NIMA-related kinase 2 is associated with poor prognoses in malignant glioma.

Eleated expression of NIMA-related kinase 2 (NEK2) was frequently observed in a variety of malignant cancers, and it appears to be involved in the initiation, maintenance, progression, metastasis of cancer and is positively associated with poor prognosis. We sought to investigate NEK2 expression and its predictive roles in malignant gliomas, and study the correlation of NEK2 protein expression with proliferation, clinical parameters, overall survival and some other parameters. We investigate NEK2 protein expression in 99 samples of malignant gliomas, including 35 WHO grade II, 22 grade III, and 42 grade IV gliomas, by immunohistochemistry and western blot (n = 50). We then made correlative analysis of protein overexpression using the Kaplan-Meier method, Log rank test, and Cox proportional-hazards model analysis. NEK2 protein was overexpressed in malignant gliomas, but not in normal brain tissues. Overexpression of NEK2 correlated with malignancy, proliferation and adverse overall survival in gliomas. Moreover, chemotherapy, resection extent and WHO grade also correlate with overall survival in gliomas. However, within WHO grade II glioma subgroup, NEK2 overexpression showed no impact on overall survival. The present study firstly reveals that NEK2 protein is widely overexpressed in gliomas. NEK2 overexpression correlates significantly with malignancy (WHO grades), proliferation (Ki-67) and prognosis in malignant gliomas. NEK2 is a potential gene therapy target and prognostic indicator.

C-Fos over-expression promotes radioresistance and predicts poor prognosis in malignant glioma.

c-Fos is a major component of activator protein (AP)-1 complex. It has been implicated in cell differentiation, proliferation, angiogenesis, invasion, and metastasis. To investigate the role of c-Fos in glioma radiosensitivity and to understand the underlying molecular mechanisms, we downregulated c-Fos gene expression by lentivirus-mediated shRNA in glioma cell lines and subsequently analyzed the radiosensitivity, DNA damage repair capacity, and cell cycle distribution. Finally, we explored its prognostic value in 41 malignant glioma patients by immunohistochemistry. Our results showed that silencing c-Fos sensitized glioma cells to radiation by increasing radiation-induced DNA double strand breaks (DSBs), disturbing the DNA damage repair process, promoting G2/M cell cycle arrest, and enhancing apoptosis. c-Fos protein overexpression correlated with poor prognosis in malignant glioma patients treated with standard therapy. Our findings provide new insights into the mechanism of radioresistance in malignant glioma and identify c-Fos as a potentially novel therapeutic target for malignant glioma patients.

Immunotherapy for malignant gliomas: current status and perspective

Despite aggressive multimodal treatment prognosis for malignant gliomas remains poor. The low efficiency of conventional cytostatic therapy forced to look for alternative approaches to treatment. This review deals with active immunotherapy using tumor vaccines and adoptive cell therapy. Vaccinotherapy may be carried out using tumor lysates or individual peptides, or mRNA. To improve the immunogenicity of vaccines dendritic cells and various immunoadjuvants are widely used. When using lysate vaccine in patients with newly diagnosed glioblastoma multiforme median progression-free survival is 9,5–18 months, and median overall survival is 16,25–35,9 months, significantly more than the historical control. Peptide vaccines to WT-1, survivin, mutated isocitrate dehydrogenase (IDHR132H), mutated epidermal growth factor receptor (EGFRvIII) are under investigation. Promising are the methods of vaccinotherapy against glioma stem cells antigens, cytomegalovirus antigens. The possibility of integration of immunotherapy in the existing treatment standards, as well as a combination of several immunotherapeutic strategies, has been studied extensively.

Expression of Notch1, MMP-2 and MMP-9 and their significance in glioma patients

To study the expression of Notch1, MMP-2 and MMP-9 in glioma patients and their relationship with progression and prognosis of gliomas. Sixty-four cases of glioma were included in this study. There were four cases of grade 1 tumor, twenty-five cases of grade 2, nine cases of grade 3, and twenty-six cases of grade 4. Immunohistochemistry (SP staining method) was used to detect the expression of Notch1, MMP-2 and MMP-9 in glioma tissues and adjacent non-tumor tissues, and the patients were followed up. Notch1, MMP-2 and MMP-9 were detected in glioma tissues but not in adjacent non-tumor tissues. The expression of Notch1 was increased with the pathological grade of the gliomas (r = 0.262, P < 0.05). The survival time of patients with strong expression of Notch1 was 31.0 months, significantly shorter than that of patients with non-strong positive (negative, weak and moderately) Notch1 expression (53.0 months, P < 0.05). Significant difference in survival time was observed between patients with negative and positive expression of MMP-9 (P < 0.05). Notch1, MMP-2 and MMP-9 are closely correlated with the progression and prognosis of malignant gliomas. Notch1 may participate in the expression regulation of MMP-2 and MMP-9. Compared with MMP-2, MMP-9 may play a more important role in determining the prognosis of malignant glioma. Notch1 and MMP-9 may become new biological markers for prognosis of patients with malignant glioma.

PO-1076 Unsupervised clustering in gene expression profiling to make prognosis for malignant gliomas

PO-1076 Unsupervised clustering in gene expression profiling to make prognosis for malignant gliomas

Abstract 4812: A novel EGFL7-derived peptide, E7C13, is a potent anti-tumor agent that inhibits angiogenesis in a beta 1 integrin- and thrombospondin-dependent manner

Abstract As a tumor grows beyond 1mm, it recruits new blood vessels through the process of angiogenesis. The selective inhibition of the vascular endothelial growth factor (VEGF) pathway increases the efficacy of chemotherapy and has beneficial effects on multiple advanced cancers, but response is often limited and the disease eventually progresses. This highlights the necessity to develop novel therapeutics that target alternate angiogenic signaling pathways. The epidermal growth factor-like domain 7 (EGFL7) is a secreted protein that is up-regulated in actively remodeling endothelium, localizing to the perivascular extracellular matrix. Inhibition of EGFL7 in zebrafish disrupts vascular tube formation during vasculogenesis, while knockout of EGFL7 in mice prevents endothelial lumen formation and tubulogenesis. EGFL7 expression is associated with poor prognosis in malignant glioma, hepatocellular carcinoma and non-small cell lung cancer, and therefore is a promising therapeutic target for anti-cancer strategies. In this study we investigated the impact of tumor-localized EGFL7 in tumor growth and angiogenesis. When EGFL7 is over-expressed in HT1080 fibrosarcoma or MDA-MB-231 breast cancer we saw no effect on tumor cell proliferation yet we observed a dramatic inhibition of tumor growth and angiogenesis in animal models. Indeed, we demonstrate that EGFL7 interacts with thrombospondin, and that it promotes endothelial cell spreading and adhesion in a beta 1 integrin- and TSP-dependent manner. In an attempt to isolate the domain of EGFL7 that is responsible for this angiogenesis inhibition activity, we identified and characterized a novel EGFL7-derived peptide, E7C13. This peptide inhibited sprouting and tube formation of human endothelial cells in vitro in 2D and 3D assays, and inhibited angiogenesis induced by tumor cells in vivo in the chicken embryo CAM assay and in the mouse DIVAA assay. Treatment of HT1080 tumor-bearing mice with E7C13 peptide intravenously at 75 mg/kg led to significantly reduced tumor growth and increased survival. Tumors from E7C13-treated animals were significantly less vascularized compared to controls. These data suggest that E7C13 is a promising new anti-vascular agent, and may provide a basis for a novel anti-angiogenesis approach to treat cancer. Citation Format: Choi-Fong Cho, Laura A. Fung, Tienabe Nsiama, Lihai Yu, Alisha Kadam, Daniela F. Quail, Katia Carmine-Simmen, Desmond Pink, Lynne-Marie Postovit, Leonard G. Luyt, John D. Lewis. A novel EGFL7-derived peptide, E7C13, is a potent anti-tumor agent that inhibits angiogenesis in a beta 1 integrin- and thrombospondin-dependent manner. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4812. doi:10.1158/1538-7445.AM2014-4812

Abstract 2194: Tyrosyl DNA phosphodiesterase I is a prognostic factor and its inhibition synergizes response to topoisomerase poisons in malignant glioma.

Abstract Malignant Glioma is the most common type of primary brain tumors in adults accounting for about 80% of all gliomas. Despite the advances in treatment and diagnosis, the prognosis of malignant glioma is still poor with a median survival less than a year for glioblastoma patients. Targeting DNA-repair mechanisms is a clinically relevant option for enhancing response to DNA-damaging anticancer agents. TDP1 has been recently discovered to be responsible for the repair of the irreversible DNA-topoisomerase I covalent complexes produced by topoisomerase I poisons. Other studies have suggested its role in the repair of the DNA damage produced by ionizing radiation and temozolomide. However, TDP1 relevance has not yet been studied in glioma. Thus the aims of this project are to identify the role of TDP1 in glioma aggressiveness and resistance to therapies. We hypothesize that high-grade gliomas possess higher TDP1 levels which are associated with lower survival and resistance to therapy. Quantitative real-time PCR analysis of TDP1 in glioma biopsies revealed a negative prognostic effect of TDP1, where the level of TDP1 mRNA was inversely correlated with patient survival. Moreover, western blot showed an overexpression of TDP1 in glioma biopsies compared to normal tissues and increased expression with higher grades. TDP1 overexpression in U87 cell lines did not induce resistance to temozolomide, topotecan, etoposide or doxorubicin. This may be related to other downstream DNA repair enzymes that need to be also modulated to fully induce drug resistance. However, TDP1 inhibition using small molecules synergizes the cytotoxicity of topotecan, etoposide, and doxorubicin, confirming thus its critical role in response to several therapeutic agents. As a conclusion, TDP1 is a new and promising prognostic factor and a modulator of therapy response in malignant glioma that may help in stratification of patients. Additionally, targeting TDP1 is a novel strategy that will widen the therapeutic options for malignant glioma where topoisomerase I and II poisons can be part of the gold standard therapy when used in combination with TDP1 inhibitors. Citation Format: Maha Al-Keilani, Supreet Agarwal, Mohammad Alqudah, Zita Sibenaller, Timothy Ryken, Mahfoud Assem. Tyrosyl DNA phosphodiesterase I is a prognostic factor and its inhibition synergizes response to topoisomerase poisons in malignant glioma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2194. doi:10.1158/1538-7445.AM2013-2194

Nimotuzumab treatment of malignant gliomas

Introduction: In spite of new alkylating medication and recently accumulated knowledge about genomics, the prognosis of malignant gliomas remains poor. The introduction of single substances interfering with tumour proliferation dynamics has been disappointing and the lessons learned indicate that a complicated network of proliferation needs time consuming, in-depth analysis in order to more specifically treat now distinguishable subgroups of a disease, which too long was thought of as a uniform entity.Areas covered: The clinical trials using the EGFR antibody nimotuzumab in the treatment of malignant gliomas are reviewed. Pending conformation in future studies the antibody might be part of the treatment of MGMT-negative, EGFR-amplified, not completely resected gliomas of adulthood and juvenile DIPG (pontine gliomas). Upcoming genomic results of the different tumour entities may suggest certain combination partners of the antibody. Recent studies of nimotuzumab indicate the reason for the lack of toxicity, which is the most attractive argument for its clinical use besides modest efficacy.Expert opinion: We await the final results on the use of the antibody together with vinorelbine and radiation therapy for the therapy of DIPG. Adult patients with MGMT-negative, EGFR amplified, not totally resected GBM may also profit from this combination therapy. TK-inhibitors combined with the antibody and irradiation may be an option for a therapeutic trial in paediatric patients.

Targeted Therapy for Brain Tumours: Role of PARP Inhibitors

The prognosis of malignant glioma and metastatic brain tumours is still extremely poor, despite recent advances in therapeutic strategies with molecular-targeted agents. Poly(ADP-ribose) polymerase (PARP) inhibitors are a promising, novel class of anticancer drugs to be used either as single agents or in combination with chemotherapy and radiotherapy. PARP-1 and PARP-2 are the only PARP proteins that bind to DNA single strand breaks (SSBs), facilitating the repair process by the base excision repair. For this reason, PARPs have been extensively investigated as targets of novel drugs that may be used to enhance the antitumour activity of SSBs inducing agents, such as the methylating compound temozolomide, which is the drug of choice for glioblastoma, or ionizing radiations. Moreover, PARP inhibitors exert cytotoxic effects in monotherapy in BRCA mutated tumours, which are defective in the homologous recombination (HR) repair. Finally, recent studies have shown that inhibition of PARP function might also induce anti-angiogenic effects which might contribute to impair tumour growth. Many clinical trials with PARP inhibitors are ongoing for the treatment of a variety of advanced solid tumours, including primary or secondary brain tumours. This review discusses the implications of targeting PARP on the design of new treatment regimens.

Survival Analysis of Patients with High-Grade Gliomas Based on Data Mining of Imaging Variables

The prediction of prognosis in HGGs is poor in the majority of patients. Our aim was to test whether multivariate prediction models constructed by machine-learning methods provide a more accurate predictor of prognosis in HGGs than histopathologic classification. The prediction of survival was based on DTI and rCBV measurements as an adjunct to conventional imaging. The relationship of survival to 55 variables, including clinical parameters (age, sex), categoric or continuous tumor descriptors (eg, tumor location, extent of resection, multifocality, edema), and imaging characteristics in ROIs, was analyzed in a multivariate fashion by using data-mining techniques. A variable selection method was applied to identify the overall most important variables. The analysis was performed on 74 HGGs (18 anaplastic gliomas WHO grades III/IV and 56 GBMs or gliosarcomas WHO grades IV/IV). Five variables were identified as the most significant, including the extent of resection, mass effect, volume of enhancing tumor, maximum B0 intensity, and mean trace intensity in the nonenhancing/edematous region. These variables were used to construct a prediction model based on a J48 classification tree. The average classification accuracy, assessed by cross-validation, was 85.1%. Kaplan-Meier survival curves showed that the constructed prediction model classified malignant gliomas in a manner that better correlates with clinical outcome than standard histopathology. Prediction models based on data-mining algorithms can provide a more accurate predictor of prognosis in malignant gliomas than histopathologic classification alone.

Abstract 1151: microRNAs affect therapeutic sensitivity of human gliobastoma to temozolomide

Abstract Glioma is among the most deadly type of cancer. In spite of the enormous improvements made the prognosis of malignant glioma has remained poor over the last decade. Many glial-derived tumors seem to be particularly resistant to apoptosis following DNA damage. MicroRNAs (miRNA) represent a novel class of small RNAs that might play a fundamental role in tumorigenesis, cell proliferation, migration and apoptosis. Temozolomide is an alkylating agent used in glioma patients that alkylates/methylates DNA. The alkylation damages the DNA and triggers the death of tumor cells. O6-methylguanine DNA methyltransferase (MGMT) is a DNA repair enzyme which removes DNA adducts. MGMT activity is frequently lost in glioblastoma in the presence of CpG island hypermethylation in the promoter region. The methylation status of the MGMT promoter is considered to be indicative of a good outcome in patients with malignant gliomas. However, in some studies the correlation between MGMT promoter methylation and MGMT expression levels are contradictory. Other possible mechanisms of MGMT modulation should exist. Therefore, we investigated the role of miRs on the regulation of MGMT expression levels. We analyzed temozolomide sensitivity of human glioma cell lines, T98G and U87MG. T98G resulted resistant to temozolomide, whereas U87MG cells were sensitive. Through a microarray analysis we provided evidences that miR-221/222 are differentially expressed in U87MG compared to T98G cells. Bioinformatics analysis through RNA Hybrid indicated a possible match between MGMT 3’UTR and miR-221/222. Luciferase assay confirmed that miR-221/222 are capable to bind the 3’UTR of MGMT and to impair its mRNA translation. Western blot and RT-PCR analysis upon synthetic pre-miR-221/222 transfection of T98G cells indicated that MGMT levels were significantly decreased. At the contrar, the transfection of U87MG cells with anti-miR-221/222 induced an increase of MGMT levels. Therefore this data indicate that MGMT is a new target of miRs -221/222. The analysis of cell death with MTT, Annexin V and colony assay upon temozolomide treatment in cells whose miR-221/222 levels were modulated, demonstrated an important role of those miRs in temozolomide sensitivity. All these data indicate that miR-221/222 might represent a new strategy for regulation of MGMT expression levels and thus temozolomide sensitivity and an improvement in chemotherapy strategy for glioblastoma patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1151. doi:10.1158/1538-7445.AM2011-1151

Brain Fatty Acid-binding Protein and ω-3/ω-6 Fatty Acids: MECHANISTIC INSIGHT INTO MALIGNANT GLIOMA CELL MIGRATION

Malignant gliomas (MG) are highly infiltrative tumors that consistently recur despite aggressive treatment. Brain fatty acid-binding protein (FABP7), which binds docosahexaenoic acid (DHA) and arachidonic acid (AA), localizes to sites of tumor infiltration and is associated with a poor prognosis in MG. Manipulation of FABP7 expression in MG cell lines affects cell migration, suggesting a role for FABP7 in tumor infiltration and recurrence. Here, we show that DHA inhibits and AA stimulates migration in an FABP7-dependent manner in U87 MG cells. We demonstrate that DHA binds to and sequesters FABP7 to the nucleus, resulting in decreased cell migration. This anti-migratory effect is partially dependent on peroxisome proliferator-activated receptor γ, a DHA-activated transcription factor. Conversely, AA-bound FABP7 stimulates cell migration by activating cyclooxygenase-2 and reducing peroxisome proliferator-activated receptor γ levels. Our data provide mechanistic insight as to why FABP7 is associated with a poor prognosis in MG and suggest that relative levels of DHA and AA in the tumor environment can make a profound impact on tumor growth properties. We propose that FABP7 and its fatty acid ligands may be key therapeutic targets for controlling the dissemination of MG cells within the brain.

Survival of high grade glioma patients depends on their age at diagnosis

Background: Although the prognosis for malignant gliomas is normally dismal, it’s not infrequent in neurooncologist’s experience to find cases with unusually prolonged survival. In order to understand what factors influence survival of high grade glioma patients, a cohort of 196 high (III-IV) grade glioma patients was investigated for possible association between i) survival and age at diagnosis; ii) survival and micronuclei in tumor tissue; iii) survival and gender; iv) micronuclei in tumor tissue and age at diagnosis. Methods: Survival analysis was performed by the Cox’ proportional hazards regression model. Results: Patients diagnosed at an older age (>64 years) had a significantly higher hazard as compared to younger patients (≤ 64 years), indicating that older patients survived shorter. On the contrary, no association was found between survival and micronuclei or gender.Conclusions: Age at diagnosis, together with other established prognostic factors such as histologic characteristics, extent of surgery and Karnofsky Performance Score may to a certain extent predict survival of high grade glioma patients.

Radiosurgery for Gliomas

Stereotactic radiosurgery is a neurosurgical modality that involves delivering a large dose of focused radiation to a lesion while sparing the surrounding normal brain tissue. The biological properties of some gliomas, specifically relating to their oxygenation and invasiveness, can make them good targets for stereotactic radiosurgery. Although randomized controlled studies are lacking, preliminary data suggest that radiosurgery may be a viable alternative for low-grade gliomas, with improved survival and a low rate of complications. Although the prognosis for malignant gliomas is poor even after radiosurgery, it is possible the radiosurgical treatment can allow the surgeon more flexibility in terms of operative planning and subsequently result in better quality of life for patients post-operatively.

Combating Immunosuppression in Glioma

Despite maximal therapy, malignant gliomas have a very poor prognosis. Patients with glioma express significant immune defects, including CD4 lymphopenia, increased fractions of regulatory T cells in peripheral blood and shifts in cytokine profiles from Th1 to Th2. Recent studies have focused on ways to combat immunosuppression in patients with glioma as well as in animal models for glioma. We concentrate on two specific ways to combat immunosuppression: inhibition of TGF-beta signaling and modulation of regulatory T cells. TGF-beta signaling can be interrupted by antisense oligonucleotide technology, TGF-beta receptor I kinase inhibitors, soluble TGF-beta receptors and antibodies against TGF-beta. Regulatory T cells have been targeted with antibodies against T-cell markers, such as CD25, CTLA-4 and GITR. In addition, vaccination against Foxp3 has been explored. The results of these studies have been encouraging; combating immunosuppression may be one key to improving prognosis in malignant glioma.

Real-time polymerase chain reaction technique determines absolute copy number of plasma methylated MGMT gene promoter copies in newly diagnosed malignant glioma patients

22073 Background: New methods for disease surveillance, quantification, and prognosis in malignant glioma are needed. Recent work has demonstrated that malignant gliomas release their DNA into the blood which bears the genetic and epigenetic aberrations in the intracranial lesion. We determined the actual plasma copy number of the methylated chemoresistance gene methylguanine methyltransferase (MGMT) in patients enrolled in clinical trials for malignant glioma as a prelude to biomarker development. Methods: This prospective NABTT CNS Consortium study was designed to determine if tumor specific plasma DNA could serve as an accurate biomarker. Plasma was collected from newly diagnosed high grade glioma patients prior to therapy and with each follow-up MRI. DNA was isolated from plasma of the first 19 patients enrolled and bisulfite treated. Quantitative PCR was performed with methylation-sensitive primers selective for the methylated MGMT promoter. A S. cerevisiae actin gene spike-in quantitative PCR technique was used to control for variations in DNA loss during the process. Resuts: Baseline plasma from 19 patients demonstrated an overall mean of 2.74 × 105 copies/mL (SEM: 7.67 × 104) of the MGMT promoter. The range of tumor specific DNA in these samples was 1.14 × 104 to 1.22 × 106 copies/mL. One of 19 patients demonstrated no detectable MGMT methylation. Conclusions: Tumor DNA in the blood of high grade glioma patients offers a unique platform to develop a biomarker to satisfy the needs of evolving treatments. This provides the possibility to assess tumor burden in a manner distinct from MRI scans which rely heavily on blood-brain barrier status. This study will eventually yield important information on initial tumor specific DNA concentrations in plasma and changes over the course of the patients' illness. No significant financial relationships to disclose.