IDH-wildtype Patients Research Articles

Prognostic impact of a lymphocyte activation-associated gene signature in GBM based on transcriptome analysis.

BackgroundGlioblastoma multiforme (GBM) is a highly, malignant tumor of the primary central nervous system. Patients diagnosed with this type of tumor have a poor prognosis. Lymphocyte activation plays important roles in the development of cancers and its therapeutic treatments.ObjectiveWe sought to identify an efficient lymphocyte activation-associated gene signature that could predict the progression and prognosis of GBM.MethodsWe used univariate Cox proportional hazards regression and stepwise regression algorithm to develop a lymphocyte activation-associated gene signature in the training dataset (TCGA, n = 525). Then, the signature was validated in two datasets, including GSE16011 (n = 150) and GSE13041 (n = 191) using the Kaplan Meier method. Univariate and multivariate Cox proportional hazards regression models were used to adjust for clinicopathological factors.ResultsWe identified a lymphocyte activation-associated gene signature (TCF3, IGFBP2, TYRO3 and NOD2) in the training dataset and classified the patients into high-risk and low-risk groups with significant differences in overall survival (median survival 15.33 months vs 12.57 months, HR = 1.55, 95% CI [1.28–1.87], log-rank test P < 0.001). This signature showed similar prognostic values in the other two datasets. Further, univariate and multivariate Cox proportional hazards regression models analysis indicated that the signature was an independent prognostic factor for GBM patients. Moreover, we determined that there were differences in lymphocyte activity between the high- and low-risk groups of GBM patients among all datasets. Furthermore, the lymphocyte activation-associated gene signature could significantly predict the survival of patients with certain features, including IDH-wildtype patients and patients undergoing radiotherapy. In addition, the signature may also improve the prognostic power of age.ConclusionsIn summary, our results suggested that the lymphocyte activation-associated gene signature is a promising factor for the survival of patients, which is helpful for the prognosis of GBM patients.

Does positive MGMT methylation outbalance the limitation of subtotal resection in glioblastoma IDH-wildtype patients?

BackgroundThe impact on survival of complete resection (CR) in patients with malignant glioma and MGMT promoter methylation on adjuvant therapy strategies has been proven in the past. However, it is not known whether a MGMT promoter methylation can compensate a subtotal resection. Therefore, we analyzed the progress of postoperative residual tumor tissue depending on the molecular tumor status.MethodsWe included all glioblastoma, IDH-wildtype (WHO grade IV) patients with postoperative residual tumor tissue, who were treated at our neurooncological department between 2010 and 2018. Correlation of molecular patterns with clinical data and survival times was performed. The results were compared to patients following CR.Results267 patients with glioblastoma, IDH-wildtype (WHO grade IV) received surgery of whom 81 patients with residual tumor were included in the analysis. MGMT promoter was methylated in 31 patients (38.27%). Median OS and PFS were significantly increased in patients with methylated MGMT promoter (mOS: 16 M vs. 13 M, p = 0.009; mPFS: 13 M vs. 5 M, p = 0.003). In comparison to survival of patients following CR, OS was decreased in patients with residual tumor regardless MGMT methylation.ConclusionOur data confirm impact of MGMT promoter methylation in patients with glioblastoma, IDH-wildtype on OS and PFS. However, in comparison to patients after CR, a methylated MGMT promoter cannot compensate the disadvantage due to residual tumor volume. In terms of personalized medicine and quality of life as major goal in oncology, neuro-oncologists have to thoroughly discuss advantages and disadvantages of residual tumor volume versus possible neurological deficits in CR.

The Influence of Gene Aberrations on Survival in Resected IDH Wildtype Glioblastoma Patients: A Single-Institution Study.

This prospective population-based study on a group of 132 resected IDH-wildtype (IDH-wt) glioblastoma (GBM) patients assesses the prognostic and predictive value of selected genetic biomarkers and clinical factors for GBM as well as the dependence of these values on the applied therapeutic modalities. The patients were treated in our hospital between June 2006 and June 2015. Clinical data and tumor samples were analyzed to determine the frequencies of TP53, MDM2, EGFR, RB1, BCR, and CCND1 gene aberrations and the duplication/deletion statuses of the 9p21.3, 1p36.3, 19q13.32, and 10p11.1 chromosome regions. Cut-off values distinguishing low (LCN) and high (HCN) copy number status for each marker were defined. Additionally, MGMT promoter methylation and IDH1/2 mutation status were investigated retrospectively. Young age, female gender, Karnofsky scores (KS) above 80, chemoradiotherapy, TP53 HCN, and CCND1 HCN were identified as positive prognostic factors, and smoking was identified as a negative prognostic factor. Cox proportional regression models of the chemoradiotherapy patient group revealed TP53 HCN and CCND1 HCN to be positive prognostic factors for both progression-free survival and overall survival. These results confirmed the influence of key clinical factors (age, KS, adjuvant oncotherapy, and smoking) on survival in GBM IDH-wt patients and demonstrated the prognostic and/or predictive importance of CCND1, MDM2, and 22q12.2 aberrations.

Pharmacoresistant seizures and IDH mutation in low-grade gliomas.

BackgroundMany low-grade gliomas (LGG) harbor isocitrate dehydrogenase (IDH) mutations. Although IDH mutation is known to be epileptogenic, the rate of refractory seizures in LGG with IDH mutation vs wild-type had not been previously compared. We therefore compared seizure pharmacoresistance in IDH-mutated and wild-type LGGs.MethodsSingle-institution retrospective study of patients with histologic proven LGG, known IDH mutation status, seizures, and ≥2 neurology clinic encounters. Seizure history was followed until histological high-grade transformation or death. Seizures requiring ≥2 changes in anti-epileptic drugs were considered pharmacoresistant. Incidence rates of pharmacoresistant seizures were estimated using competing risks methodology.ResultsOf 135 patients, 25 patients (19%) had LGGs classified as IDH wild-type. Of those with IDH mutation, 104 (94.5%) were IDH1 R132H; only 6 were IDH2 R172K. 120 patients (89%) had tumor resection, and 14 (10%) had biopsy. Initial post-surgical management included observation (64%), concurrent chemoradiation (23%), chemotherapy alone (9%), and radiotherapy alone (4%). Seizures became pharmacoresistant in 24 IDH-mutated patients (22%) and in 3 IDH wild-type patients (12%). The 4-year cumulative incidence of intractable seizures was 17.6% (95% CI: 10.6%-25.9%) in IDH-mutated and 11% (95% CI: 1.3%-32.6%) in IDH wild-type LGG (Gray’s P-value = .26).Conclusions22% of the IDH-mutated patients developed pharmacoresistant seizures, compared to 12% of the IDH wild-type tumors. The likelihood of developing pharmacoresistant seizures in patients with LGG-related epilepsy is independent to IDH mutation status, however, IDH-mutated tumors were approximately twice as likely to experience LGG-related pharmacoresistant seizures.

TAMI-51. IDENTIFYING NEW TUMOR MICROENVIRONMENT (TME) CONTEXTS OF VULNERABILITY IN GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most frequent and aggressive adult brain tumor with 85% of patients dying within two years. New effective precision medicine therapies are urgently required, especially for isocitrate dehydrogenase wild-type (IDHwt) disease. Despite efforts to subtype patients based on molecular profiles, this approach has yet failed to direct treatment strategies. Further interrogation of the tumor microenvironment (TME) across molecular subtypes and identification of new TME specific subtypes may guide new directions for future therapies. Here, we analysed transcriptomic data from selected GLIOTRAIN(www.gliotrain.eu)(n=120) and TCGA(n=69) IDHwt patients. Firstly, the microenvironment cell population (MCP)-counter method (a gene-expression-based TME deconvolution tool) was validated for use in the brain tumor setting using quantitative multiplex immunohistochemistry. In this context, immune markers (CD20/CD3/CD68/CD8) were significantly correlated with MCP-counter scores. We are currently optimizing and validating a vessel-density and microglial RNA-signature to provide a more robust representation of brain TME. Next, using MCP-counter, the TME composition of IDHwt tumors was assessed within proneural (24%), classical (38%) and mesenchymal (38%) subtypes. We initially classified the GLIOTRAIN cohort into 3 novel clusters characterised by differences in TME composition and validated our findings in the TCGA cohort. A TME-high group (37%) is characterized by elevated presence of lymphocytes and myeloid cells, and presents a high level of immune checkpoint genes: PDCD1(PD1) and CTLA4. In addition, the presence of tertiary lymphoid structures (TLS) is a feature of TMEhigh/mesenchymal+ patients. This finding has been validated by IHC and RNA-signature. TME-med (38%) displayed heterogenous immune populations and the TME-low (25%) represented an ‘immune-desert’ group. There was no significant difference in OS based on these TME subtypes(p=0.50). We hypothesise that PD1/CTLA4 blockade might be an effective treatment strategy in TME-high patients. These hypotheses will be tested (in the adjuvant setting) using appropriate syngeneic disease models which incorporate surgical resection.

PATH-03. CLINICAL UTILITY OF NEXT GENERATION SEQUENCING IN IDH-WILDTYPE GLIOBLASTOMA: THE DANA-FARBER CANCER INSTITUTE EXPERIENCE

Abstract BACKGROUND Comprehensive next generation sequencing (NGS) is available through many academic institutions and commercial entities, and is incorporated in practice guidelines for glioblastoma (GBM). We retrospective evaluated the practice patterns and utility of incorporating NGS data into routine care of GBM patients at a clinical trials-focused academic center. METHODS We identified 1,011 consecutive adult patients with histologically confirmed GBM with OncoPanel testing, a targeted exome NGS platform of 447 cancer-associated genes at Dana Farber Cancer Institute (DFCI), from 2013-2019. We selected and retrospectively reviewed clinical records of all IDH-wildtype GBM patients treated at DFCI. RESULTS We identified 557 GBM IDH-wildtype patients, of which 227 were male (40.7%). OncoPanel testing revealed 833 single nucleotide variants and indels in 44 therapeutically relevant genes (Tier 1 or 2 mutations) including PIK3CA (n=51), BRAF (n=9), FGFR1 (n=8), MSH2 (n=4), MSH6 (n=2) and MLH1 (n=1). Copy number analysis revealed 509 alterations in 18 therapeutically relevant genes including EGFR amplification (n= 186), PDGFRA amplification (N=39) and CDKN2A/2B homozygous loss (N=223). Median overall survival was 17.5 months for the whole cohort. Seventy-four therapeutic clinical trials accrued 144 patients in the upfront setting (25.9%) and 203 patients (36.4%) at recurrence. Altogether, NGS data for 107 patients (19.2%) were utilized for clinical trial enrollment or targeted therapy indications. High mutational burden (&amp;gt;17mutations/Mb) was identified in 11/464 samples (2.4%); of whom 3/11 received immune checkpoint blockade. Four patients received compassionate use therapy targeting EGFRvIII (rindopepimut, n=2), CKD4/6 (abemaciclib, n=1) and BRAFV600E (dabrafenib/trametinib, n=1). CONCLUSION While NGS has greatly improved diagnosis and molecular classification, we highlight that NGS remains underutilized in selecting therapy in GBM, even in a setting where clinical trials and off-label therapies are relatively accessible. Continued efforts to develop better targeted therapies and efficient clinical trial design are required to maximize the potential benefits of genomically-stratified data.

Elevated plasma 20S proteasome chymotrypsin-like activity is correlated with IL-8 levels and associated with an increased risk of death in glial brain tumor patients.

IntroductionIn cancer treatment an attempt has been made to pharmacologically regulate the proteasome functions, thus the aim was to test whether 20S proteasome chymotrypsin-like (ChT-L) activity has a role in glial brain tumors. Furthermore, we analyzed the correlation between proteasome activity and IL-8, CCL2, NF-κB1 and NF-κB2 concentrations, which impact on brain tumors has already been indicated.MethodsPlasma 20S proteasome ChT-L activity was assayed using the fluorogenic peptide substrate Suc-Leu-Leu-Val-Tyr-AMC in the presence of SDS. IL-8, CCL2, NF-κB1 and NF-κB2 concentration was analyzed with the use of ELISA method. Immunohistochemistry for IDH1-R132H was done on 5-microns–thick formalin-fixed, paraffin-embedded tumor sections with the use of antibody specific for the mutant IDH1-R132H protein. Labelled streptavidin biotin kit was used as a detection system.ResultsBrain tumor patients had statistically higher 20S proteasome ChT-L activity (0.649 U/mg) compared to non-tumoral individuals (0.430 U/mg). IDH1 wild-type patients had statistically higher 20S proteasome ChT-L activity (1.025 U/mg) compared to IDH1 mutants (0.549 U/mg). 20S proteasome ChT-L activity in brain tumor patients who died as the consequence of a tumor (0.649) in the following 2 years was statistically higher compared to brain tumor patients who lived (0.430 U/mg). In brain tumor patients the 20S proteasome ChT-L activity positively correlated with IL-8 concentration.ConclusionsElevated 20S proteasome ChT-L activity was related to the increased risk of death in glial brain tumor patients. A positive correlation between 20S proteasome ChT-L activity and IL-8 concentration may indicate the molecular mechanisms regulating glial tumor biology. Thus research on proteasomes may be important and should be carried out to verify if this protein complexes may represent a potential therapeutic target to limit brain tumor invasion.

Identification of tumor microenvironment-related genes in lower-grade gliomas by mining TCGA database.

BackgroundLower-grade gliomas (LGGs) are ubiquitous and fatal branches of brain neoplasm. Finding biomarkers related to diagnosis and treatment is essential for the treatment of LGG. It is possible to reveal the potential links between tumor microenvironment and overall survival (OS) in LGG by mining the mRNA expression profile from the TCGA database. Our primary purpose was to explore key genes that can be applied for diagnosis or treatment in LGG microenvironment.MethodsBased on the ESTIMATE algorithm, the immune and stromal scores were calculated to measure the extent of infiltration of immune cells and stromal cells, respectively. The LGG samples from TCGA database were assigned into high- or low-score groups per the immune and stromal scores and differentially expressed genes (DEGs) were selected by comparing gene expression levels in the two groups. Functional enrichment analysis and protein-protein interaction (PPI) networks were performed to analyze DEGs. Finally, selected DEGs were validated using another independent LGG cohort from CGGA dataset.ResultsThe results indicated that immune/stromal scores correlated with LGG prognosis. Furtherly, survival analysis conducted for each subtype shown that immune/stromal scores were only significantly associated with the prognosis of astrocytoma, IDH-wildtype, and there was no significant statistical difference in the other subtypes. Functional enrichment analysis and protein-protein interaction (PPI) networks further showed that the upregulated DEGs were primarily involved in immune response, plasma membrane, and cytokine binding. Accordingly, a series of genes that have significant impacts on prognosis and are significantly associated with the tumor microenvironment were obtained.ConclusionsBased on the ESTIMATE algorithm, we first explored the relationship between immune/stromal scores and prognosis in different subtypes of LGG and the result shown that the scores were only strongly associated with the prognosis of astrocytoma, IDH-wildtype. Furtherly, a comprehensive bioinformatics analysis of the gene expression profiles of astrocytoma, IDH-wildtype patients was conducted, CASP8, TRIM6, TRIM38, PARP9, NMI, EPSTI1, DTX3L and AGBL2 were identified as tumor microenvironment-related genes, may be involved in the occurrence, development, and invasion of LGG.

Extent of resection and molecular pathologic subtype are potent prognostic factors of adult WHO grade II glioma

We evaluated prognostic factors of adult low-grade glioma (LGG) according to the new 2016 WHO classification. Records of 153 patients diagnosed with WHO grade II LGG between 2003 and 2015 were retrospectively reviewed. Based on the 2016 WHO classification, 80 patients (52.3%) had diffuse astrocytoma, IDH-mutant; 45 (29.4%) had oligodendroglioma, IDH-mutant and 1p/19q-codeleted (ODG); and 28 (18.3%) had diffuse astrocytoma, IDH-wildtype. Gross total resection (GTR) was performed in 71 patients (46.4%), subtotal resection in 31 (20.3%), partial resection in 43 (28.1%), and biopsy in 8 (5.2%). One hundred two patients (66.7%) received postoperative radiotherapy. The 5- and 10-year progression-free survival (PFS) rates were 72.7% and 51.5%, respectively, and the 5- and 10-year overall survival (OS) rates were 82.5% and 63.5%, respectively. GTR and IDH-mutant and/or 1p/19q codeletion were favorable prognostic factors for PFS and OS. Patients with IDH-wildtype had significantly decreased OS. Among patients with ODG who underwent GTR, no recurrence was observed after radiotherapy. Patients who underwent non-GTR frequently experienced recurrence after radiotherapy (IDH-mutant: 47.6%, IDH-wildtype: 57.9%). In conclusion, molecular classification of LGG was of prognostic relevance, with IDH-wildtype patients having a particularly poor outcome, regardless of the treatment. Favorable results were observed in patients who underwent GTR.

Long-term efficacy of surgical resection with or without adjuvant therapy for treatment of secondary glioblastoma in adults.

BackgroundThere are limited studies on treatment strategies and associated clinical outcomes in patients with secondary glioblastoma (sGBM). We sought to investigate the prognostic factors and treatment decisions in a retrospective cohort of patients with sGBM.MethodsOne hundred and seventy-one patients with sGBM who met the screening criteria were included in this study. Kaplan–Meier survival analysis and Cox survival analysis were used to detect prognostic factors. R (v3.5.0) and SPSS software (v25.0, IBM) were used to perform statistical analyses.ResultsThe median overall survival was 303 days (range 23–2237 days) and the median progression-free survival was 229 days (range 33–1964 days) in patients with sGBM. When assessing the relationship between adjuvant treatment outcome and extent of resection (EOR), the results showed that patients underwent gross total resection can benefit from postoperative radiotherapy and chemotherapy, but not in patients underwent subtotal resection. In addition, we also found that aggressive adjuvant therapy can significantly improve clinical outcomes of IDH1-mutated patients but no significant prognostic value for IDH1-wildtyped patients. The univariate Cox regression analyses demonstrated that EOR, adjuvant therapy, and postoperative Karnofsky Performance Scores were prognostic factors for patients with sGBM, and multivariate COX analysis confirmed that adjuvant therapy and EOR were independent prognostic factors.ConclusionsFor patients with sGBM, aggressive postoperative adjuvant therapy after gross total resection was recommended. However, we did not detect a benefit in IDH1-wildtype patients in our cohort.

QOLP-38. PATIENT REPORTED OUTCOMES IN GLIOMA: THE ROLE OF IDH MUTATION ON QUALITY OF LIFE AND MOOD

Abstract Isocitrate dehydrogenase 1 (IDH) mutation has important clinical prognostic value in glioma patients conferring improved survival and better neurocognitive function (NCF) compared to IDH wild type (IDH-WT) patients. It is not known whether IDH mutation status has an impact on patient reported outcomes (PRO). The goal of this single institution retrospective study was to examine the impact of IDH-mutation status on PRO’s in patients who also completed neuropsychological evaluation. METHODS Out of 101 glioma patients referred for neuropsychological evaluation between 2018–2019, 73 completed the Functional Assessment of Cancer Therapy-Brain (FACT-Br; non-completion due to severe cognitive impairment, poor English). In addition to the total score, the FACT-Br includes 5 subscales of wellbeing (Physical, Social, Emotional, Functional, and Brain specific symptoms). 69 patients completed the Beck Depression Inventory (BDI) and 61 completed the Beck Anxiety Inventory (BAI). Self-reported symptoms were compared between those with IDH-Mut vs IDH-WT by ANOVA. RESULTS Diagnoses included glioblastoma (20), diffuse astrocytoma grade II/III (29) and oligodendroglioma grade II/III (24). 29/73 (40%) patients were IDH-mut. FACT-Br total scores did not differ between IDH-WT and IDH-Mut glioma patients (F=2.685; p=ns). Separate analyses of the 5 FACT-Br subscales showed that only the emotional functioning subscale differed significantly, with IDH-Mut patients reporting better emotional functioning than IDH-WT patients (F=7.4; p&amp;lt; 0.05). BDI and BAI scores did not differ by group (F= 2.2 and 1.9, respectively; p=NS). CONCLUSIONS IDH mutation was related to patient reported emotional status on the FACT-Br in this mixed clinical sample of glioma patients. Analysis is complicated by the heterogeneity of the sample and retrospective nature of the study. Routine inclusion of PRO’s as standard of care may allow a more comprehensive understanding of the impact of IDH throughout the natural history of glioma.

Systemic screening identifies GABRD, a subunit gene of GABAA receptor as a prognostic marker in adult IDH wild-type diffuse low-grade glioma

Currently, no reliable prognostic biomarkers have been identified for adult IDH wild-type (WT) diffuse low grade glioma (LGG). With data from The Cancer Genome Atlas (TCGA)-LGG, we examined the prognostic value of GABAA receptor subunits in adult IDH WT LGG. Using 2016 WHO CNS tumor classification, we re-classified the TCGA-LGG and identified 95 IDH WT patients. Among 16 GABAA receptor subunit genes with RNA-seq data, eight genes showed significantly different expression in IDH WT LGG compared with IDH mutant (MT) cases. Among these genes, only GABRD expression was related to overall survival (OS) status. Preserved GABRD expression was independently associated with longer OS (HR: 0.799, 95%CI: 0.691-0.925, p = 0.003) in IDH WT LGG. GABRD expression showed a moderately negative correlation with tumor infiltration macrophage (TIM) and CSF1 expression. The methylation status of 34 CpG sites across GABRD gene was checked and only cg13916816 showed a moderately negative correlation with GABRD expression. In conclusion, GABRD expression might serve as a potential independent prognostic marker in patients with IDH WT LGG. Meanwhile, its expression was negatively correlated with the extent of TIM, which might help to explain the favorable survival outcome. Cg13916816 might be a critical CpG site influencing GABRD expression in IDH WT LGG.

Genome-wide investigation of intragenic DNA methylation identifies ZMIZ1 gene as a prognostic marker in glioblastoma and multiple cancer types.

DNA methylation has long been recognized as a tumor-promoting factor when aberrantly regulated in the promoter region of genes. However, the effect of intragenic DNA methylation remains poorly understood on the clinical aspects of cancer. Here, we first evaluated the significance of intragenic DNA methylation for survival outcomes of cancer patients in a genome-wide manner. Glioblastoma patients with hypermethylated intragenic regions exhibited better survival than hypomethylated patients. Enrichment analyses of intragenic DNA methylation profiles with epigenetic signatures prioritized the intragenic DNA methylation of ZMIZ1 as a possible glioblastoma prognostic marker that is independent of MGMT methylation in IDH1 wild-type patients. This intragenic region harbored molecular signatures of alternative transcription across many cell types. Furthermore, we found that the intragenic region of ZMIZ1 can serve as a molecular marker in multiple cancers including astrocytomas, bladder cancer and renal cell carcinoma according to DNA methylation status. Finally, in vitro and in vivo experiments uncovered the role of ZMIZ1 as a driver of tumor cell migration. Altogether, our results identify ZMIZ1 as a prognostic marker in cancer and highlight the clinical significance of intragenic methylation in cancer.

Diffusion Tensor Imaging Reveals Microstructural Heterogeneity of Normal-Appearing White Matter and Related Cognitive Dysfunction in Glioma Patients.

Immunohistochemical data based on isocitrate–dehydrogenase (IDH) mutation status have redefined glioma as a whole-brain disease, while occult tumor cell invasion along white matter fibers is inapparent in conventional magnetic resonance imaging (MRI). The functional and prognostic impact of focal glioma may however relate to the extent of white matter involvement. We used diffusion tensor imaging (DTI) to investigate microstructural characteristics of whole-brain normal-appearing white matter (NAWM) in relation to cognitive functions as potential surrogates for occult white matter involvement in glioma. Twenty patients (12 IDH-mutated) and 20 individually matched controls were preoperatively examined using DTI combined with a standardized neuropsychological examination. Tumor lesions including perifocal edema were masked, and fractional anisotropy (FA) as well as mean, radial, and axial diffusivity (MD, RD, and AD, respectively) of the remaining whole-brain NAWM were determined by using Tract-Based Spatial Statistics and histogram analyses. The relationship between extratumoral white matter integrity and cognitive performance was examined using partial correlation analyses controlling for age, education, and lesion volumes. In patients, mean FA and AD were decreased as compared to controls, which agrees with the notion of microstructural impairment of NAWM in glioma patients. Patients performed worse in all cognitive domains tested, and higher anisotropy and lower MD and RD values of NAWM were associated with better cognitive performance. In additional analyses, IDH-mutated and IDH-wildtype patients were compared. Patients with IDH-mutation showed higher FA, but lower MD, AD, and RD values as compared to IDH-wildtype patients, suggesting a better preserved microstructural integrity of NAWM, which may relate to a less infiltrative nature of IDH-mutated gliomas. Diffusion-based phenotyping and monitoring microstructural integrity of extratumoral whole-brain NAWM may aid in estimating occult white matter involvement and should be considered as a complementary biomarker in glioma.

Combination of Enasidenib and Venetoclax Shows Superior Anti-Leukemic Activity Against IDH2 Mutated AML in Patient-Derived Xenograft Models

Mutations in isocitrate dehydrogenase 2 (IDH2) promote AML pathogenesis through production of 2-hydroxyglutarate (2-HG). Enasidenib is an inhibitor of mutant IDH2 activity and induces the differentiation of IDH2-mutated leukemic blasts. In a phase I/II clinical trial, enasidenib monotherapy resulted in an overall response rate of 40% and median duration of response of 6 months in relapsed/refractory AML (Stein et. al. Blood 2017).We previously discovered that mutant IDH activity sensitizes AML cells to BCL-2 inhibition through accumulation of 2-HG (Chan et. al. Nature Medicine 2015). Pharmacologic inhibition of BCL-2 activity with venetoclax, a highly specific BH3 mimetic, preferentially targets IDH-mutated human AML cells. In a phase II clinical trial of venetoclax monotherapy, IDH-mutated relapsed/refractory AML patients had a response rate of 33% compared to 10% in IDH-wildtype patients (Konopleva et. al. Cancer Discovery 2016).Based on the above findings, we hypothesized that combination therapy with enasidenib and venetoclax may demonstrate superior anti-leukemic activity in comparison to single agents in the treatment of IDH2-mutant AML. However, given that the mechanism by which IDH mutations increase BCL-2 dependence is via 2-HG, reduction of 2-HG with enasidenib may antagonize venetoclax activity. As such, we further hypothesized that a sequential dosing schedule may be superior to concurrent dosing.To test our hypotheses, we conducted a preclinical study to evaluate the efficacy of monotherapy versus combination therapy in reducing the leukemic burden in three patient-derived xenograft (PDX) models of human IDH2-mutant AML. All three PDX models were derived from samples with co-occurring IDH2R140Q and NPM1c mutations. Engrafted animals were randomly assigned to one of six treatment arms (N=5 per arm): vehicle (arm 1), enasidenib alone (arm 2), venetoclax alone (arm 3), concurrent combination (arm 4), and sequential combinations (arms 5 and 6; see Figure 1 for details). Enasidenib and venetoclax were administered by oral gavage at a dose of 40 mg/kg twice a day and 100 mg/kg daily, respectively. Tumor burden was measured in bone marrow samples collected immediately prior to treatment and every 2 weeks during the 12-week treatment period.Concurrent combination treatment (arm 4) resulted in the greatest reduction in leukemia engraftment compared to all other treatment arms, including the sequential dosing arms, in two of the three models (#1 and #2, henceforth termed “responders”; Figure 2A). Although venetoclax monotherapy reduced engraftment in all three models, persistent disease above a threshold of 0.1% was detectable in 12 of 13 animals by flow cytometry (9 of 13 by ddPCR) after 12 weeks of treatment (Figure 2B). In contrast, disease was detectable in only 2 of 9 animals (0 of 9 by ddPCR) treated with concurrent therapy in responders. In the remaining model (#3, henceforth termed “non-responder”), combination therapy was not superior to venetoclax monotherapy but importantly, co-treatment with enasidenib did not antagonize venetoclax activity. Interestingly, enasidenib monotherapy increased expression of myeloid differentiation markers, CD15 and CD11b, only in responders, indicating that differentiation might be a precondition for responsiveness to concurrent therapy. We confirmed that the lack of response in non-responders was not due to selection of an IDH2 wildtype clone or failure to block 2-HG production by enasidenib.To gain insights into the mechanism by which enasidenib might enhance venetoclax sensitivity, we performed quantitative intracellular flow cytometry staining for the anti-apoptotic proteins BCL-2, BCL-xL and MCL-1 in leukemic cells collected after 12 weeks of treatment. Enasidenib monotherapy resulted in a significant decrease in BCL-2 expression in responders. The reduction in anti-apoptotic protein expression could potentiate mitochondrial priming and sensitization to venetoclax.In summary, our findings demonstrate that concurrent combination therapy with enasidenib and venetoclax is a promising therapeutic approach for IDH2-mutated AML. Responsiveness to combination therapy is associated with enasidenib-induced differentiation and reduction in anti-apoptotic protein expression. Our findings support ongoing and future clinical investigations in combination therapies with mutant IDH and BCL-2 inhibitors. DisclosuresCojocari:AbbVie Inc: Employment. Phillips:AbbVie Inc: Employment, Equity Ownership, Patents & Royalties. Leverson:AbbVie Inc: Employment, Equity Ownership, Patents & Royalties. MacBeth:Celgene Corporation: Employment, Equity Ownership. Nicolay:Agios: Employment. Narayanaswamy:Agios: Employment. Ronseaux:Agios: Employment. Liu:Agios: Employment, Equity Ownership. Chan:AbbVie: Research Funding; Genentech: Research Funding; Celgene: Research Funding.

Surgical management of lower-grade glioma in the spotlight of the 2016 WHO classification system.

According to the 2016 WHO classification lower-grade gliomas consist of three groups: IDH-mutated and 1p/19q co-deleted, IDH-mutated and IDH-wildtype tumors. The aim of this study was to evaluate the impact of surgical therapy for lower-grade gliomas with a particular focus on the molecular subgroups. This is a bi-centric retrospective analysis including 299 patients, who underwent treatment for lower-grade glioma between 1990 and 2016. All tumors were re-classified according to the 2016 WHO classification. Data concerning baseline and tumor characteristics, overall survival, different treatment modalities and functional outcome were analyzed. A total of 112 (37.5%) patients with IDH-mutation and 1p/19q co-deletetion, 86 (28.8%) patients with IDH-mutation and 101 (33.8%) patients with IDH-wildtype tumors were identified. The median overall survival (mOS) differed significantly between the groups (p < 0.001). Surgical resection was performed in 226 patients and showed significantly improved mOS compared to the biopsy group (p = 0.001). Gross total resection (GTR) was associated with better survival (p = 0.007) in the whole cohort as well as in the IDH-mutated and IDH-wildtype groups compared to partial resection or biopsy. IDH-wildtype patients presented a significant survival benefit after combined radio-chemotherapy compared to radio- or chemotherapy alone (p = 0.02). Good clinical status (NANO) was associated with longer OS (p = 0.001). The impact of surgical treatment on the outcome of lower-grade gliomas depends to a great extent on the molecular subtype of the tumors. Patients with more aggressive tumors (IDH-wildtype) seem to profit from more intensive treatment like GTR, multiple resections and combined radio-/chemotherapy.

BCAT1 is a New MR Imaging-related Biomarker for Prognosis Prediction in IDH1-wildtype Glioblastoma Patients

Isocitrate dehydrogenase 1 (IDH1)-wildtype glioblastoma (GBM) has found to be accompanied with increased expression of branched-chain amino acid trasaminase1 (BCAT1), which is associated with tumor growth and disease progression. In this retrospective study, quantitative RT-PCR, immunohistochemistry, and western blot were performed with GBM patient tissues to evaluate the BCAT1 level. Quantitative MR imaging parameters were evaluated from DSC perfusion imaging, DWI, contrast-enhanced T1WI and FLAIR imaging using a 3T MR scanner. The level of BCAT1 was significantly higher in IDH1-wildtype patients than in IDH1-mutant patients obtained in immunohistochemistry and western blot. The BCAT1 level was significantly correlated with the mean and 95th percentile-normalized CBV as well as the mean ADC based on FLAIR images. In addition, the 95th percentile-normalized CBV from CE T1WI also had a significant correlation with the BCAT1 level. Moreover, the median PFS in patients with BCAT1 expression <100 was longer than in those with BCAT1 expression ≥100. Taken together, we found that a high BCAT1 level is correlated with high CBV and a low ADC value as well as the poor prognosis of BCAT1 expression is related to the aggressive nature of GBM.

Expression and clinical significance of podoplanin in gliomas

Objective To analyze the expression of podoplanin (PDPN) in gliomas, and to investigate its relationship to clinical features and prognosis of gliomas. Methods Clinical data and mRNA microarray data of 301 glioma samples from Chinese Glioma Genome Atlas (CGGA) database were collected, and the expression of PDPN was analyzed. GSE16011 mRNA microarray datasets, TCGA RNA sequencing database and REMBRANDT mRNA microarray datasets were used as validation sets. Kaplan-Meier survival and Cox regression analysis were used to estimate the role of PDPN in the prognosis of patients. In addition, Gene ontology (GO) analysis was performed to study the function of genes positively related to expression of PDPN. Results In CGGA, the expression of PDPN protein was the highest in grade IV gliomas (0.62±0.07, all P<0.05), while was the lowest in grade II gliomas (-0.59±0.06, all P<0.05); the expression of PDPN protein in IDH1 wild-type patients was higher than that in mutant patients (0.48±0.07 and -0.58±0.07 respectively, P<0.05). The cumulative survival rate of patients with high expression of PDPN protein was significantly lower than that of low expression group (P<0.05). The above characteristics of PDPN protein obtained similar results in the other three databases. Multivariate analysis showed that age, pathological grade, the expression of PDPN protein and radiotherapy were independent factors affecting the survival of glioma patients (all P<0.05), which could be used for prognosis. PDPN was found related to the immune response, extracellular matrix regulation, cell adhesion and migration and other biological processes of glioma. Conclusion PDPN could promote the development of gliomas and thus be used as a prognostic biomarker and potential therapeutic target. Key words: Glioma; Podoplanin; Gene expression; Prognosis

Prognostic importance of temozolomide-induced neutropenia in glioblastoma, IDH-wildtype patients.

Standard treatment for patients with primary glioblastoma (GBM) includes surgery, radiotherapy, and concomitant and adjuvant temozolomide (TMZ). Recent reports have demonstrated that TMZ-induced myelosuppression correlates with survival in patients with GBM. However, those results were evaluated before the 2016 revision of the World Health Organization classification. This study examined whether myelosuppression during concomitant TMZ phase correlates with prognosis in GBM, IDH-wildtype patients. We examined circulating blood cell counts in 50 patients with GBM, IDH-wildtype who received the standard treatment protocol between August 2005 and November 2015. We assessed relationships between rates of decrease in blood cells (white blood cells (WBC), neutrophils, lymphocytes, red blood cells, and platelets) during the concomitant TMZ phase and overall survival (OS) using univariate and multivariate analyses including other clinicopathological factors (age, sex, Karnofsky Performance Status (KPS), extent of resection, O6-methylguanine-DNA methyltransferase (MGMT) status). Log-rank testing revealed that age, KPS, extent of resection, MGMT status, and decrease rates of WBC, neutrophils, and platelets correlated significantly with OS. On multivariate analysis, age, MGMT status, and decrease rate of neutrophils correlated significantly with OS. Patients with a ≥40% decrease in neutrophils showed significantly longer OS than those with <40% (hazard ratio=2.815; 95% confidence interval=1.177-7.038; P=0.0196). A decrease of ≥40% in neutrophils represents a predictor of good prognosis for GBM, IDH-wildtype. Blood cell counts during the concomitant TMZ phase can help predict OS in patients with GBM, IDH-wildtype receiving the standard treatment protocol.

IGFBP2 expression predicts IDH-mutant glioma patient survival.

Mutations of the isocitrate dehydrogenase (IDH) 1 and 2 genes occur in ~80% of lower-grade (WHO grade II and grade III) gliomas. Mutant IDH produces (R)-2-hydroxyglutarate, which induces DNA hypermethylation and presumably drives tumorigenesis. Interestingly, IDH mutations are associated with improved survival in glioma patients, but the underlying mechanism for the difference in survival remains unclear. Through comparative analyses of 286 cases of IDH-wildtype and IDH-mutant lower-grade glioma from a TCGA data set, we report that IDH-mutant gliomas have increased expression of tumor-suppressor genes (NF1, PTEN, and PIK3R1) and decreased expression of oncogenes(AKT2, ARAF, ERBB2, FGFR3, and PDGFRB) and glioma progression genes (FOXM1, IGFBP2, and WWTR1) compared with IDH-wildtype gliomas. Furthermore, each of these genes is prognostic in overall gliomas; however, within the IDH-mutant group, none remains prognostic except IGFBP2 (encodinginsulin-like growth factor binding protein 2). Through validation in an independent cohort, we show that patients with low IGFBP2 expressiondisplay a clear advantage in overall and disease-free survival, whereas those with high IGFBP2 expressionhave worse median survival than IDH-wildtype patients. These observations hold true across different histological and molecular subtypes of lower-grade glioma. We propose therefore that an unexpected biological consequence of IDH mutations in glioma is to ameliorate patient survival by promoting tumor-suppressor signaling while inhibiting that of oncogenes, particularly IGFBP2.