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Pituitary neuroendocrine tumors (PitNETs) exhibiting aggressive, treatment-refractory behavior are the rare subset that progress after surgery, conventional medical therapies, and an initial course of radiation and are characterized by unrelenting growth and/or metastatic dissemination. Two groups of patients with PitNETs were sequenced: a prospective group of patients (n = 66) who consented to sequencing prior to surgery and a retrospective group (n = 26) comprised of aggressive/higher risk PitNETs. A higher mutational burden and fraction of loss of heterozygosity (LOH) was found in the aggressive, treatment-refractory PitNETs compared to the benign tumors (p = 1.3 × 10-10 and p = 8.5 × 10-9, respectively). Within the corticotroph lineage, a characteristic pattern of recurrent chromosomal LOH in 12 specific chromosomes was associated with treatment-refractoriness (occurring in 11 of 14 treatment-refractory versus 1 of 14 benign corticotroph PitNETs, p = 1.7 × 10-4). Across the cohort, a higher fraction of LOH was identified in tumors with TP53 mutations (p = 3.3 × 10-8). A machine learning approach identified loss of heterozygosity as the most predictive variable for aggressive, treatment-refractory behavior, outperforming the most common gene-level alteration, TP53, with an accuracy of 0.88 (95% CI: 0.70-0.96). Aggressive, treatment-refractory PitNETs are characterized by significant aneuploidy due to widespread chromosomal LOH, most prominently in the corticotroph tumors. This LOH predicts treatment-refractoriness with high accuracy and represents a novel biomarker for this poorly defined PitNET category.
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Perda de Heterozigosidade , Tumores Neuroendócrinos , Neoplasias Hipofisárias , Humanos , Perda de Heterozigosidade/genética , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/patologia , Tumores Neuroendócrinos/genética , Tumores Neuroendócrinos/patologia , Tumores Neuroendócrinos/terapia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Idoso , Estudos Retrospectivos , Mutação/genética , Estudos ProspectivosRESUMO
PURPOSE: Multidisciplinary tumor boards (MTBs) integrate clinical, molecular, and radiological information and facilitate coordination of neuro-oncology care. During the COVID-19 pandemic, our MTB transitioned to a virtual and multi-institutional format. We hypothesized that this expansion would allow expert review of challenging neuro-oncology cases and contribute to the care of patients with limited access to specialized centers. METHODS: We retrospectively reviewed records from virtual MTBs held between 04/2020-03/2021. Data collected included measures of potential clinical impact, including referrals to observational or therapeutic studies, referrals for specialized neuropathology analysis, and whether molecular findings led to a change in diagnosis and/or guided management suggestions. RESULTS: During 25 meetings, 32 presenters discussed 44 cases. Approximately half (n = 20; 48%) involved a rare central nervous system (CNS) tumor. In 21% (n = 9) the diagnosis was changed or refined based on molecular profiling obtained at the NIH and in 36% (n = 15) molecular findings guided management. Clinical trial suggestions were offered to 31% (n = 13), enrollment in the observational NCI Natural History Study to 21% (n = 9), neuropathology review and molecular testing at the NIH to 17% (n = 7), and all received management suggestions. CONCLUSION: Virtual multi-institutional MTBs enable remote expert review of CNS tumors. We propose them as a strategy to facilitate expert opinions from specialized centers, especially for rare CNS tumors, helping mitigate geographic barriers to patient care and serving as a pre-screening tool for studies. Advanced molecular testing is key to obtaining a precise diagnosis, discovering potentially actionable targets, and guiding management.
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Neoplasias do Sistema Nervoso Central , Pandemias , Humanos , Estudos Retrospectivos , Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/terapia , Equipe de Assistência ao Paciente , Encaminhamento e ConsultaRESUMO
PURPOSE: Incidence, prevalence, and survival are population-based statistics describing cancer burden. The National Cancer Institute's (NCI) Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) specializes in tumor biology and outcomes for 12 rare CNS tumor types selected for their importance in adults, research interest, or potential for targeted treatment. The aim of this study was to update incidence, prevalence, and survival statistics for these tumors. METHODS: The Central Brain Tumor Registry of the United States (CBTRUS) database, a combined dataset of Centers for Disease Control and Prevention's (CDC) National Program of Cancer Registries (NPCR) and NCI's Surveillance, Epidemiology and End Results (SEER) data, was used to calculate average annual age-adjusted incidence rates (AAAIR) per 100,000 population overall and by sex, race-ethnicity, and age for diagnosis years 2008-2019. Incidence time trends were calculated for diagnosis years 2004-2019. NPCR data were used to calculate relative survival rates. Point prevalence on December 31, 2019 was estimated using annual age-specific incidence and survival. RESULTS: AAAIR was 1.47 per 100,000 for these tumors combined, with highest incidence in ependymomas (AAAIR = 0.41/100,000). Most tumor types were more common in males, adults (ages 40 + years) or children (ages < 15 years), and non-Hispanic White individuals. Ependymomas were the most prevalent tumor type (19,320 cases) followed by oligodendrogliomas (14,900 cases). Ependymomas had the highest five-year survival (90.6%) and primary CNS sarcomas the lowest (7.7%). CONCLUSIONS: These data provide means to measure the impact of clinical care and evaluate new therapies and the evolving histopathology definitions in rare CNS tumor types.
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Neoplasias Encefálicas , Neoplasias do Sistema Nervoso Central , Ependimoma , Criança , Adulto , Masculino , Humanos , Estados Unidos/epidemiologia , Neoplasias Encefálicas/diagnóstico , Neoplasias do Sistema Nervoso Central/epidemiologia , Sistema de Registros , Incidência , Programa de SEERRESUMO
PURPOSE: Temozolomide (TMZ), a cytotoxic DNA alkylating agent, is the main chemotherapy used for the treatment of high grade astrocytomas. The active alkylator, methylhydrazine, is not recovered in urine and thus renal function is not expected to affect clearance. Prescribing information for TMZ states pharmacokinetics have not been studied in adults with poor renal function, eGFR < 36 mL/min/1.73 m2. We reviewed our clinical experience with TMZ in patients with impaired renal function to evaluate safety of administering full dose TMZ. METHODS: The primary endpoint was to characterize the incidence and severity of thrombocytopenia in patients with eGFR < 60 mL/min/1.73 m2 who received TMZ for treatment of high grade gliomas (HGG) or primary CNS lymphoma (PCNSL). Secondary endpoints included incidence and severity of neutropenia, lymphopenia hepatotoxicity, and number of TMZ cycles administered. Medical records of patients with HGG or PCNSL treated with TMZ from October 1, 2016-September 30, 2019 were accessed to identify cases for this study. RESULTS: Thirty-two patients were eligible for this study. Of the seven patients with eGFR < 36 mL/min/1.73m2, 38/39 cycles (97%) were completed without grade 3-4 thrombocytopenia. No patients experienced grade 3-4 neutropenia, and grade 3-4 lymphopenia occurred in 5 cycles (15%). One patient discontinued TMZ 7 days prior to completion of radiation due to thrombocytopenia. CONCLUSION: Hematologic toxicity in patients with severe renal dysfunction, eGFR < 36 mL/min/1.73m2, is similar to that of patients with normal renal function. Severe renal impairment does not preclude use of temozolomide, but cautious monitoring of blood counts is warranted.
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Neoplasias Encefálicas , Glioma , Nefropatias , Linfopenia , Metilidrazinas , Neutropenia , Trombocitopenia , Adulto , Antineoplásicos Alquilantes/efeitos adversos , Neoplasias Encefálicas/patologia , Dacarbazina/efeitos adversos , Glioma/patologia , Humanos , Nefropatias/induzido quimicamente , Nefropatias/tratamento farmacológico , Metilidrazinas/uso terapêutico , Neutropenia/induzido quimicamente , Neutropenia/tratamento farmacológico , Temozolomida/efeitos adversosRESUMO
PURPOSE: Both IDH1-mutated and wild-type gliomas abundantly display aberrant CpG island hypermethylation. However, the potential role of hypermethylation in promoting gliomas, especially the most aggressive form, glioblastoma (GBM), remains poorly understood. METHODS: We analyzed RRBS-generated methylation profiles for 11 IDH1WT gliomas (including 7 GBMs), 24 IDH1MUT gliomas (including 6 GBMs), and 5 normal brain samples and employed TCGA GBM methylation profiles as a validation set. Upon classification of differentially methylated CpG islands by IDH1 status, we used integrated analysis of methylation and gene expression to identify SPINT2 as a top cancer related gene. To explore functional consequences of SPINT2 methylation in GBM, we validated SPINT2 methylation status using targeted bisulfite sequencing in a large cohort of GBM samples. We assessed DNA methylation-mediated SPINT2 gene regulation using 5-aza-2'-deoxycytidine treatment, DNMT1 knockdown and luciferase reporter assays. We conducted functional analyses of SPINT2 in GBM cell lines in vitro and in vivo. RESULTS: We identified SPINT2 as a candidate tumor-suppressor gene within a group of CpG islands (designated GT-CMG) that are hypermethylated in both IDH1MUT and IDH1WT gliomas but not in normal brain. We established that SPINT2 downregulation results from promoter hypermethylation, and that restoration of SPINT2 expression reduces c-Met activation and tumorigenic properties of GBM cells. CONCLUSIONS: We defined a previously under-recognized group of coordinately methylated CpG islands common to both IDH1WT and IDH1MUT gliomas (GT-CMG). Within GT-CMG, we identified SPINT2 as a top cancer-related candidate and demonstrated that SPINT2 suppressed GBM via down-regulation of c-Met activation.
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Metilação de DNA , Regulação Neoplásica da Expressão Gênica , Glioblastoma/prevenção & controle , Isocitrato Desidrogenase/genética , Glicoproteínas de Membrana/genética , Mutação , Proteínas Proto-Oncogênicas c-met/metabolismo , Animais , Apoptose , Proliferação de Células , Ilhas de CpG , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-met/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Aim: Adult medulloblastomas (MB) are rare, and optimal post-craniospinal irradiation (CSI) chemotherapy is not yet defined. We investigated hematological toxicity in patients treated with platinum-etoposide (EP) post-CSI. Methods: Retrospective, single-institution study to determine hematological toxicity in adult MB patients treated with EP (1995-2022). Results: Thirteen patients with a median follow-up of 50 months (range, 10-233) were analyzed. Four discontinued treatment due to toxicity, one after 1, 3 after 3 cycles. Hematological toxicities included grade 3 (5 patients) and grade 4 (6 patients). Two patients experienced post-treatment progression and died 16 and 37 months from diagnosis. Conclusion: Post-CSI EP demonstrates acceptable hematological toxicity in adult MB. However, the small cohort precludes definitive survival outcome conclusions. Prospective studies for comprehensive comparisons with other regimens are needed in this context.
Our study aimed to understand the effect of a chemotherapy combination (platinum and etoposide) on blood counts in adult patients with medulloblastoma after craniospinal radiation. Medulloblastoma is a rare brain cancer in adults. We analyzed data from 13 adult patients with medulloblastoma. The results show that the treatment leads to significant blood count-related side effects. Four of the patients discontinued their treatment early. Blood counts improved again after completion of treatment. Two patients had the tumor grow back after treatment and died later. Overall, the effect from this chemotherapy combination on blood counts was felt to be acceptable. The number of patients in this study was small, and more research is needed to determine the overall effectiveness of this treatment.
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Neoplasias Cerebelares , Etoposídeo , Meduloblastoma , Humanos , Masculino , Estudos Retrospectivos , Adulto , Feminino , Meduloblastoma/radioterapia , Meduloblastoma/tratamento farmacológico , Etoposídeo/efeitos adversos , Etoposídeo/administração & dosagem , Adulto Jovem , Pessoa de Meia-Idade , Neoplasias Cerebelares/radioterapia , Neoplasias Cerebelares/tratamento farmacológico , Neoplasias Cerebelares/terapia , Doenças Hematológicas/induzido quimicamente , Doenças Hematológicas/etiologia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Seguimentos , Adolescente , Radiação Cranioespinal/efeitos adversos , Platina/uso terapêuticoRESUMO
INTRODUCTION: Outcomes for patients with high grade gliomas have changed little over the past thirty years. This realization prompted renewed efforts to increase flexibility in the design and conduct of clinical brain tumor trials. AREAS COVERED: This manuscript reviews the development of clinical trial methods, challenges and considerations of flexible clinical trial designs, approaches to improve identification and testing of active agents for high grade gliomas, and evaluation of their delivery to the central nervous system. EXPERT OPINION: Flexibility can be introduced in clinical trials in several ways. Flexible designs tout smaller sample sizes, adaptive modifications, fewer control arms, and inclusion of multiple arms in one study. Unfortunately, modifications in study designs cannot address two challenges that are largely responsible for the lack of progress in treating high grade gliomas: 1) the identification of active pharmaceutical agents and 2) the delivery of these agents to brain tumor tissue in therapeutic concentrations. To improve the outcomes of patients with high grade gliomas efforts must be focused on the pre-clinical screening of drugs for activity, the ability of these agents to achieve therapeutic concentrations in non-enhancing tumors, and a willingness to introduce novel compounds in minimally pre-treated patient populations.
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Neoplasias Encefálicas , Glioma , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Glioma/tratamento farmacológico , HumanosRESUMO
Most tumors, including brain tumors, are sporadic. However, a small subset of CNS tumors are associated with hereditary cancer conditions like Lynch Syndrome (LS). Here, we present a case of an oligodendroglioma, IDH-mutant and 1p/19q-codeleted, and LS with a germline pathogenic PMS2 mutation. To our knowledge, this has only been reported in a few cases in the literature. While the family history is less typical of LS, previous studies have indicated the absence of a significant family history in patient cohorts with PMS2 mutations due to its low penetrance. Notably, only a handful of studies have worked on characterizing PMS2 mutations in LS, and even fewer have looked at these mutations in the context of brain tumor development. This report aims to add to the limited literature on germline PMS2 mutations and oligodendrogliomas. It highlights the importance of genetic testing in neuro-oncology.
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Straight femur alignment during dual-energy X-ray absorptiometry (DXA) acquisition is assumed to help ensure accurate bone mineral density (BMD) measurement. Use of bilateral femur positioners may not result in straight femur alignment. To assess the effect of a bilateral femur positioner on DXA results, we compared a standard fixed-width bilateral femur positioner with an adjustable-width positioner that allowed for straight femur alignment. BMD values obtained from the adjustable-width bilateral femur positioner were highly correlated (R(2)=0.98-0.99) with those obtained using a fixed-width positioner. The mean bias in BMD between the fixed- and adjustable-width positioner was low (-0.001 to +0.006g/cm(2)) at all proximal femur regions of interest. In this study, the use of a fixed-width bilateral femur positioner and associated deviations in femur alignment have little consequence on BMD measurement.
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Absorciometria de Fóton/métodos , Densidade Óssea , Fêmur/diagnóstico por imagem , Fêmur/metabolismo , Postura , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Between 2011 and 2016, O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation testing at University of California Los Angeles (UCLA) was performed through LabCorp, using a threshold of 2 to distinguish MGMT methylated from unmethylated tumors. In this study, we sought to determine whether the magnitude of the methylation score correlated with outcome. METHODS: We identified 165 newly diagnosed glioblastoma (GBM) isocitrate dehydrogenase (IDH) wild-type and temozolomide-treated upfront patients at UCLA and Kaiser Permanente Los Angeles with LabCorp-derived quantitative MGMT scores obtained on pretreatment tissue samples. Using LabCorp's threshold, we found 102 unmethylated and 63 methylated patients. We then further substratified each group based on the magnitude of the score, and performed Kaplan-Meier and Cox regression analyses of overall survival (OS) and progression-free survival (PFS). RESULTS: We validated that the standard LabCorp threshold of 2 could separate our cohort by survival, showing longer OS and PFS for MGMT methylated patients vs unmethylated patients. Cox regression analysis confirmed that MGMT (<1) patients had worse outcome, with OS and PFS hazard ratios of 2.375 (P = .053) and 2.463 (P = .023), respectively, when compared to the MGMT (1-1.99) patients. Contrary to our expectation, when we substratified the ≥2 (methylated) group, we did not find a dose-dependent relationship between the magnitude of MGMT methylation and improved survival. CONCLUSIONS: The MGMT unmethylated group contains a partially methylated group (greater than 1) that shares survival benefits similar to the methylated group. However, we did not demonstrate an association of very high methylation scores with increased survival. These findings will require validation in additional independent clinical data sets.
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BACKGROUND: Since its approval for use in recurrent glioblastoma (GBM), the survival benefit of bevacizumab (Bev) remains to be demonstrated. To address this issue, we retrospectively examined survival from first recurrence in patients treated with Bev, lomustine (CCNU), or Bev/CCNU. METHODS: We identified 168 primary GBM patients diagnosed at UCLA and Kaiser Permanente LA who received upfront radio-chemotherapy, followed by Bev and/or CCNU at first recurrence. Three patient groups, contemporaneously diagnosed from 2009 through 2015, were identified: (1) patients treated with Bev alone (n = 49), (2) CCNU alone (CCNU 09-15) (n = 36), and (3) Bev/CCNU (n = 53). Another CCNU control group (n = 30) diagnosed from 2001 through 2004 (CCNU 01-04) was also derived. We measured tumor size at first recurrence treatment initiation, using bidimensional (2D) and volumetric (3D) techniques, and analyzed overall survival (OS) from first recurrence. RESULTS: Among the entire cohort, larger tumor size at first recurrence was associated with poorer survival. The CCNU 01-04 group had similar tumor size as the Bev arms and low Bev crossover (7%). Treatment with Bev was associated with improved survival in patients with large tumor 2D measurements: Median OS for Bev and Bev/CCNU groups were 6.71 mo (n = 27) and 6.97 mo (n = 36) vs 4.03 mo (n = 10) in CCNU 01-04. Analysis by 3D measurement yielded similar results. Interestingly, the CCNU 09-15 group showed the highest survival, likely due to smaller tumor size and crossover to Bev (69%). CONCLUSION: Survival advantage from Bev treatment was observed only among patients with large tumor burden as determined by either 2D or 3D measurement.
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Elastomers based on poly(dimethylsiloxane) (PDMS) are promising materials for fabrication of a wide range of microanalytical systems due to their mechanical and optical properties and ease of processing. To date, however, quantitative studies that demonstrate reliable and reproducible methods for attachment of binding groups that capture complex receptor proteins of relevance to biomedical applications of PDMS microsystems have not been reported. Herein we describe methods that lead to the reproducible capture of a transmembrane protein, the human epidermal growth factor (EGF) receptor, onto PDMS surfaces presenting covalently immobilized antibodies for EGF receptor, and subsequent isolation of the captured receptor by mechanical transfer of the receptor onto a chemically functionalized surface of a gold film for detection. This result is particularly significant because the physical properties of transmembrane proteins make this class of proteins a difficult one to analyze. We benchmark the performance of antibodies to the human EGF receptor covalently immobilized on PDMS against the performance of the same antibodies physisorbed to conventional surfaces utilized in ELISA assays through the use of EGF receptor that was (32)P-radiolabeled in its autophosphorylation domain. These results reveal that two pan-reactive antibodies for the EGF receptor (clones H11 and 111.6) and one phosphospecific EGF receptor antibody (clone pY1068) capture the receptor on both PDMS and ELISA plates. When using H11 antibody to capture EGF receptor and subsequent treatment with a stripping buffer (NaOH and sodium dodecylsulfate) to isolate the receptor, the signal-to-background obtained using the PDMS surface was 82 : 1, exceeding the signal-to-background measured on the ELISA plate (<48 : 1). We also characterized the isolation of captured EGF receptor by mechanical contact of the PDMS surface with a chemically functionalized gold film. The efficiency of mechanical transfer of the transmembrane protein from the PDMS surface was found to be 75-81%. However, the transfer of non-specifically bound protein was substantially less than 75%, thus leading to the important finding that mechanical transfer of the EGF receptor leads to an approximately four-fold increase in signal-to-background from 20 : 1 to 88 : 1. The signal-to-background obtained following mechanical transfer is also better than that obtained using ELISA plates and stripping buffer (<48 : 1). The EGF receptor is a clinically important protein and the target of numerous anticancer agents and thus these results, when combined, provide guidance for the design of PDMS-based microanalytical systems for the capture and isolation of complex and clinically important transmembrane proteins.
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Tecnologia Biomédica/métodos , Dimetilpolisiloxanos/química , Receptores ErbB/isolamento & purificação , Receptores ErbB/metabolismo , Técnicas Analíticas Microfluídicas/métodos , Modelos Biológicos , Anticorpos/imunologia , Ensaio de Imunoadsorção Enzimática , Receptores ErbB/imunologia , Humanos , Ligação Proteica , Propriedades de SuperfícieRESUMO
Mutant isocitrate dehydrogenase (IDH) 1/2 converts α-ketoglutarate (α-KG) to D-2 hydroxyglutarate (D-2-HG), a putative oncometabolite that can inhibit α-KG-dependent enzymes, including ten-eleven translocation methylcytosine dioxygenase (TET) DNA demethylases. We recently established that miRNAs are components of the IDH1 mutant-associated glioma CpG island methylator phenotype (G-CIMP) and specifically identified MIR148A as a tumor-suppressive miRNA within G-CIMP. However, the precise mechanism by which mutant IDH induces hypermethylation of MIR148A and other G-CIMP promoters remains to be elucidated. In this study, we demonstrate that treatment with exogenous D-2-HG induces MIR148A promoter methylation and transcriptional silencing in human embryonic kidney 293T (293T) cells and primary normal human astrocytes. Conversely, we show that the development of MIR148A promoter methylation in mutant IDH1-overexpressing 293T cells is abrogated via treatment with C227, an inhibitor of mutant IDH1 generation of D-2-HG. Using dot blot assays for global assessment of 5-hydroxymethylcytosine (5-hmC), we show that D-2-HG treatment reduces 5-hmC levels, whereas C227 treatment increases 5-hmC levels, strongly suggesting TET inhibition by D-2-HG. Moreover, we show that withdrawal of D-2-HG treatment reverses methylation with an associated increase in MIR148A transcript levels and transient generation of 5-hmC. We also demonstrate that RNA polymerase II binds endogenously to the predicted promoter region of MIR148A, validating the hypothesis that its transcription is driven by an independent promoter.Implications: Establishment of D-2-HG as a necessary and sufficient intermediate by which mutant IDH1 induces CpG island methylation of MIR148A will help with understanding the efficacy of selective mutant IDH1 inhibitors in the clinic. Mol Cancer Res; 16(6); 947-60. ©2018 AACR.
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Metilação de DNA/genética , Glutaratos/metabolismo , Isocitrato Desidrogenase/metabolismo , MicroRNAs/metabolismo , Humanos , MutaçãoRESUMO
Background: Promoter mutation in the human telomerase reverse transcriptase gene (hTERT) occurs in ~75% of primary glioblastoma (GBM). Although the mutation appears to upregulate telomerase expression and contributes to the maintenance of telomere length, its clinical significance remains unclear. Methods: We performed hTERT promoter genotyping on 303 isocitrate dehydrogenase 1 wild-type GBM tumors treated with standard chemoradiotherapy. We also stratified 190 GBM patients from the database of The Cancer Genome Atlas (TCGA) by hTERT gene expression. We analyzed overall and progression-free survival by Kaplan-Meier and Cox regression. Results: We detected hTERT promoter mutation in 75% of the patients. When included as the only biomarker, hTERT mutation was not prognostic in our patient cohort by Cox regression analysis. However, when hTERT and O6-DNA methylguanine-methyltransferase (MGMT) were included together, we observed an interaction between these 2 factors. To further investigate this interaction, we performed pairwise comparison of the 4 patient subcohorts grouped by hTERT-MGMT status (MUT-M, WT-M, MUT-U, and WT-U). MGMT methylated patients showed improved survival only in the presence of hTERT promoter mutation: MUT-M versus MUT-U (overall survival of 28.3 vs 15.9 mos, log-rank P < .0001 and progression-free survival of 15.4 vs 7.86 mo, log-rank P < .0001). These results were confirmed by Cox analyses. Analogously, the cohort from TCGA demonstrated survival benefit of MGMT promoter methylation only in patients with high hTERT expression. In addition, hTERT mutation was negatively prognostic in our MGMT unmethylated patients, while the analogous association with high expression was not observed in the cohort from TCGA. Conclusion: The prognostic influence of MGMT promoter methylation depends on hTERT promoter mutation. This interaction warrants further mechanistic investigation.
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Quimiorradioterapia/mortalidade , Metilação de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Glioblastoma/mortalidade , Isocitrato Desidrogenase/genética , Mutação/genética , Regiões Promotoras Genéticas/genética , Telomerase/genética , Proteínas Supressoras de Tumor/genética , Idoso , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Feminino , Glioblastoma/genética , Glioblastoma/patologia , Glioblastoma/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Prognóstico , Taxa de SobrevidaRESUMO
Here we show that ionic self-assembly of simple biological tectons can be used to synthesize stable and highly ordered molecular structures. In particular, nucleotides and charged polypeptides can be assembled to form a complex analogous to DNA under relatively benign conditions. The combination of polylysine and pure dGMP leads to a fourfold ladder structure stabilizing an interior G-quartet structure by four polypeptide scaffolds. Making use of the Watson-Crick Gâ¶C base pairing motive leads to double-stranded complexes. Interestingly, these complexes show stable DNA-like organization in aqueous solutions, as proven by gel electrophoresis and intercalation experiments.
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Surface-induced ordering of liquid crystals (LCs) offers the basis of a label-free analytical technique for the detection of surface-bound biomolecules. The orientation-dependent energy of interaction of a LC with a surface (anchoring energy of LC), in particular, is both sensitive to the presence of surface-bound molecules and easily quantified. Herein, we report a study that analyzes a simple model of twisted nematic LC systems and thereby identifies surfaces with LC anchoring energies in the range of 0.5 microJ/m(2) to 2.0 microJ/m(2) to be optimal for use with LC-based analytical methods. Guided by these predictions, we demonstrate that analytic surfaces possessing anchoring energies within this range can be fabricated with a high level of precision (< 0.1 microJ/m(2)) through formation of monolayers of organothiols (with omega-functional groups corresponding to oligoethyleneglycols and amines) on gold films deposited by physical vapor deposition at oblique angles of incidence. Finally, by using the human epidermal growth factor receptor (EGFR) as a model protein analyte, we have characterized the influence of the anchoring energies of the surfaces on the response of the LC to the presence of surface-bound EGFR. These results, when combined with (32)P-radiolabeling of the EGFR to independently quantify the surface concentration of EGFR, permit identification of surfaces that allow use of LCs to report surface densities of EGFR of 30-40 pg/mm(2). Overall, the results reported in this paper guide the design of surfaces for use in LC-based analytical systems.
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Técnicas Biossensoriais/métodos , Materiais Revestidos Biocompatíveis/química , Receptores ErbB/análise , Receptores ErbB/química , Cristais Líquidos/química , Polímeros/química , Análise Serial de Proteínas/métodos , Teste de Materiais , Ligação Proteica , Propriedades de SuperfícieRESUMO
Mixed surfactant-polyelectrolyte multilayer films were fabricated by both ionic self-assembly and spin assembly. A polycation [PEI = poly(ethylenimine)] was deposited from a dilute solution, while a polyanion (PAZO = poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]) was deposited from a mixture containing a fixed concentration of polyanion and various concentrations of the anionic surfactant sodium dodecyl sulfate (SDS). Coadsorption of SDS and PAZO onto PEI layers was observed using both deposition methods and attributed to strong PEI-SDS interactions and entropic factors. Increasing the concentration of SDS resulted in films containing progressively less adsorbed PAZO. No further reduction in the amount of adsorbed PAZO was observed above the SDS critical micelle concentration. We attribute the film growth behavior to a fast adsorption of SDS onto PEI, followed by a slower adsorption of PAZO onto the remaining unoccupied binding sites. We observe that SDS interpenetrates throughout the PAZO and PEI layers, increasing the surface hydrophobicity of both. We observed similar behavior for both ionically self-assembled and spin-assembled systems.