Disposable stochastic sensors obtained by nanolayer deposition of copper, graphene, and copper-graphene composite on silk for the determination of isocitrate dehydrogenases 1 and 2.

Three disposable stochastic sensors designed using nanolayer deposition of copper (Cu), graphene (GR), and copper-graphene (Cu-GR) composite on the silk textile, as substrate, were modified with chitosan (n=371-744), for biomedical analysis. Isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) served as model analytes for molecular recognition and quantification in biological samples such as whole blood and brain tumor tissue samples. The best sensitivities (3.77×107s µg mL-1 for IDH1, and 1.88×107s µg mL-1 for IDH2) and the lowest limits of quantification (10-2fg mL-1 for IDH1, and 5×10-2fg mL-1 for IDH2) for both IDH1 and IDH2 were recorded for the disposable stochastic sensors based on chitosan/graphene nanolayer. Very good correlations between the screening method based on disposable stochastic sensors and enzyme-linked immunosorbent assay (ELISA) were obtained; this was also proved by the results obtained using the paired t-test.

Prognostic value of pre-irradiation FET PET in patients with not completely resectable IDH-wildtype glioma and minimal or absent contrast enhancement.

In glioma patients, complete resection of the contrast-enhancing portion is associated with improved survival, which, however, cannot be achieved in a considerable number of patients. Here, we evaluated the prognostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in not completely resectable glioma patients with minimal or absent contrast enhancement before temozolomide chemoradiation. Dynamic FET PET scans were performed in 18 newly diagnosed patients with partially resected (n = 8) or biopsied (n = 10) IDH-wildtype astrocytic glioma before initiation of temozolomide chemoradiation. Static and dynamic FET PET parameters, as well as contrast-enhancing volumes on MRI, were calculated. Using receiver operating characteristic analyses, threshold values for which the product of paired values for sensitivity and specificity reached a maximum were obtained. Subsequently, the prognostic values of FET PET parameters and contrast-enhancing volumes on MRI were evaluated using univariate Kaplan-Meier and multivariate Cox regression (including the MTV, age, MGMT promoter methylation, and contrast-enhancing volume) survival analyses for progression-free and overall survival (PFS, OS). On MRI, eight patients had no contrast enhancement; the remaining patients had minimal contrast-enhancing volumes (range, 0.2-5.3 mL). Univariate analyses revealed that smaller pre-irradiation FET PET tumor volumes were significantly correlated with a more favorable PFS (7.9 vs. 4.2 months; threshold, 14.8 mL; P = 0.012) and OS (16.6 vs. 9.0 months; threshold, 23.8 mL; P = 0.002). In contrast, mean tumor-to-brain ratios and time-to-peak values were only associated with a longer PFS (P = 0.048 and P = 0.045, respectively). Furthermore, the pre-irradiation FET PET tumor volume remained significant in multivariate analyses (P = 0.043), indicating an independent predictor for OS. Our results suggest that pre-irradiation FET PET parameters have a prognostic impact in this subgroup of patients.

Upfront Therapy of Aggressive/High-Risk Low-Grade Glioma: Single-Institution Outcome Analysis of Temozolomide-Based Radio-Chemotherapy and Adjuvant Chemotherapy.

OBJECTIVE: To report clinical outcomes of temozolomide (TMZ)-based radio-chemotherapy and adjuvant chemotherapy in patients with aggressive/high-risk low-grade glioma (LGG). METHODS: Medical records of patients defined as aggressive/high-risk LGG based on clinicoradiologic and/or histomorphologic features treated between 2009 and 2016 in an academic neuro-oncology unit with upfront postoperative radiotherapy at time of initial diagnosis with concurrent and adjuvant TMZ were reviewed, retrospectively. RESULTS: In total, 64 patients with median age of 38 years at initial diagnosis were included. Histomorphologically, patients were classified into oligodendroglioma, mixed oligoastrocytoma, and astrocytoma. Molecular markers such as isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion were used to classify 37 of 64 (58%) patients into molecularly defined entities comprising oligodendroglioma (IDH-mutant with 1p/19q codeletion), IDH-mutant astrocytoma (immunohistochemistry or gene sequencing), and IDH-wild-type astrocytoma (gene sequencing). All 64 patients completed planned conventionally fractionated focal conformal radiotherapy (median dose 55.8 Gy) with concurrent TMZ. Fifty-nine patients received further adjuvant TMZ for a median of 12 cycles. Adjuvant TMZ was stopped prematurely in 6 (9%) patients due to toxicity or early disease progression. At a median follow-up of 56.7 months, 5-year Kaplan-Meier estimates of progression-free survival and overall survival for the study cohort were 74.6% and 84.3%, respectively. Five-year overall survival was 87.5%, 90.4%, and 71.9% for oligodendroglioma, mixed oligoastrocytoma, and astrocytoma, respectively (P = 0.42) Similar estimates for molecularly defined oligodendroglioma, IDH-mutant astrocytoma, and IDH-wild-type astrocytoma were 85.8%, 90%, and 66.7%, respectively (P = 0.87). CONCLUSIONS: Upfront TMZ-based concurrent radio-chemotherapy and adjuvant TMZ chemotherapy provides acceptable survival outcomes in aggressive/high-risk LGG with modest toxicity.

Prognostic Role of EYA4 in Lower Grade Glioma with IDH1 Mutation and 1p19q Co-Deletion.

BACKGROUND: Eyes absent 4 (EYA4) participates in an important role in various cancers. Patients with low EYA4 expression have significantly favorable prognosis compared with those with high EYA4 expression. However, the expression and role of EYA4 in lower grade glioma (LGG) has not been fully elucidated. METHODS: The R2 and UCSC Xena browser based on data from 284 cases in GSE16011 from Gene Expression Omnibus datasets and 530 cases of patients with LGG in The Cancer Genome Atlas database were extracted for bioinformatic analyses. The EYA4 expression in different subtypes of LGG was detected. Kaplan-Meier survival curves were generated to explore the association between EYA4 expression and overall survival (OS) in both datasets. RESULTS: Patients with LGG with lower EYA4 expression had significantly longer 5- and 10-year OS in 2 datasets (P < 0.001). By matching histological subtypes and gene expression profiles of patients with LGG, oligoastrocytoma and oligodendroglioma groups had lower EYA4 expression and longer OS compared with the astrocytoma group (P < 0.05). Patients with IDH1 mutations and 1p19q co-deletion had longer 5- and 10-year OS (P < 0.001), and EYA4 expression was significantly downregulated in these patients (P < 0.001). CONCLUSIONS: This study suggests that EYA4 can be used as a prognostic marker and provide a potential therapeutic target in patients with LGG with IDH1 mutation and 1p19q co-deletion.

TROP-2, 5hmC, and IDH1 Expression in Anaplastic Thyroid Carcinoma.

BACKGROUND: Anaplastic thyroid carcinoma (ATC), a highly aggressive malignancy, has no effective treatment to date. Trophoblast cell-surface antigen 2 (TROP-2), a transmembrane glycoprotein, has been suggested to be a promising novel target for sacituzumab govitecan, an antibody-drug conjugate. 5-Hydroxymethylcytosine (5hmC) has a role in tumor suppression and promoting modification. Additionally, isocitrate dehydrogenase 1 (IDH1) mutations are strongly associated with increased overall survival in gliomas and worse prognosis in leukemias. This study attempts to evaluate the immunoexpression of TROP-2, 5hmC, and IDH1 in ATCs and to determine their potential impact in targeted therapy. METHODS: Twenty-four ATCs were retrieved, with 9 cases that occurred de novo and 15 cases derived from either papillary thyroid carcinoma (PTC) or follicular thyroid carcinoma (FTC). Sections were immunostained with TROP-2, 5hmC, and IDH1 antibodies, and evaluated using the QuPath program. The t tests were performed using SPSS software. RESULTS: TROP-2 was detected in 12 ATCs with 9 cases demonstrating a high expression and in all PTC components, and absent in all FTC components of secondary ATCs. 5hmC expression was moderately reduced in PTC and FTC components and markedly reduced in ATC. The entire cohort showed a total absence of IDH1. CONCLUSIONS: Increased TROP-2 immunoexpression in some ATCs supports that these patients may potentially benefit from an antibody-drug conjugate therapy targeting TROP-2. Markedly reduced 5hmC expression suggests that 5hmC may be used as potential therapeutic targets for ATC. The total lack of IDH1 R132H mutation by immunostain indicates that it has no prognostic and therapeutic value in ATC.

Yet another utility for isocitrate dehydrogenase.1: Can it serve as an immunomarker to assess tumor margins in gliomas?

BACKGROUND: Isocitrate dehydrogenase-1 (IDH1) mutation is now an established early event in gliomagenesis. The ability to detect this mutation by several techniques including immunohistochemistry makes it a significant marker for diagnosing and prognosticating gliomas. This study was done to assess the expression of mutant IDH1 in different grades of gliomas and evaluate its utility in differentiating reactive gliosis from glioma and defining surgical margins of these tumors in the operative specimens. MATERIALS AND METHODS: A total of fifty cases including equal number of Grade I, II, III, and IV gliomas and gliosis were included in the study. Formalin-fixed, paraffin-embedded tissue sections from these lesions were immunostained with IDH1 and Ki-67 antibody, and percentage of tumor cells that stained positive with these markers was assessed. RESULTS: Grades II, III, and IV showed consistent immunopositivity for IDH1. No immunostaining was noted in Grade I glioma and gliosis. Mean Ki-67 labeling index correlated with grades of gliomas with low activity in Grade I and high activity in Grade IV. Individual tumor cells infiltrating into adjacent normal brain parenchyma also stained positive with IDH1 antibody. CONCLUSION: Immunostaining for IDH1 mutation can be utilized as a reliable marker in the precise diagnosis of diffuse gliomas and also in objective assessment of surgical margins to differentiate gliomas from gliosis.

Isocitrate dehydrogenase variants in cancer - Cellular consequences and therapeutic opportunities.

Abnormal metabolism is common in cancer cells and often correlates with mutations in genes encoding for enzymes involved in small-molecule metabolism. Isocitrate dehydrogenase 1 (IDH1) is the most frequently mutated metabolic gene in cancer. Cancer-associated substitutions in IDH1 and IDH2 impair wild-type production of 2-oxoglutarate and reduced nicotinamide adenine dinucleotide phosphate (NADPH) from isocitrate and oxidised nicotinamide adenine dinucleotide phosphate (NADP+ ), and substantially promote the IDH variant catalysed conversion of 2-oxoglutarate to d-2-hydroxyglutarate (d-2HG). Elevated d-2HG is a biomarker for some cancers, and inhibition of IDH1 and IDH2 variants is being pursued as a medicinal chemistry target. We provide an overview of the types of cancer-associated IDH variants, discuss some of the proposed consequences of altered metabolism as a result of elevated d-2HG, summarise therapeutic efforts targeting IDH variants and identify areas for future research.

A high-throughput SAMDI-mass spectrometry assay for isocitrate dehydrogenase 1.

The enzyme isocitrate dehydrogenase 1 (IDH1) catalyzes the conversion of isocitrate to alpha-ketoglutarate (αKG) and has emerged as an important therapeutic target for glioblastoma multiforme (GBM). Current methods for assaying IDH1 remain poorly suited for high-throughput screening of IDH1 antagonists. This paper describes a high-throughput and quantitative assay for IDH1 that is based on the self-assembled monolayers for matrix-assisted laser desorption/ionization-mass spectrometry (SAMDI-MS) method. The assay uses a self-assembled monolayer presenting a hydrazide group that covalently captures the αKG product of IDH1, where it can then be detected by MALDI-TOF mass spectrometry. Co-capture of an isotopically-labeled αKG internal standard allows the αKG concentration to be quantitated. The assay was used to analyze a series of standard αKG solutions and produced minimal error in measured αKG concentration values. The suitability of the assay for high-throughput analysis was evaluated in a 384-sample biochemical IDH1 screen. Cells expressing IDH1 were lysed and the lysate was applied to the monolayer to capture αKG, which was then quantitated using the SAMDI-MS assay. Cells in which IDH1 expression was reduced by small-interfering RNA exhibited a corresponding decrease in αKG concentration as measured by the assay. Application of the assay toward the high-throughput screening of IDH1 inhibitors or knockdown agents may facilitate the discovery of treatments for GBM.

Magnetic Resonance Spectroscopic Assessment of Isocitrate Dehydrogenase Status in Gliomas: The New Frontiers of Spectrobiopsy in Neurodiagnostics.

BACKGROUND: In the era of integrated genomic-histologic analysis of brain tumors, new biomarkers have been introduced as diagnostic, prognostic, and therapeutic indicators. The analysis of the mutation in the isocitrate dehydrogenase (IDH) genes IDH1 and IDH2 has provided important diagnostic and prognostic information for patients affected by diffuse glioma (i.e., the presence of the mutation has been related to an increased survival rate). The reference standard of IDH mutation detection has been its assessment in surgical specimens, immunohistochemistry, and/or genetic sequencing. Knowing the IDH status information preoperatively would be of great importance, because it has been related to tumor progression and the response to treatment. The oncometabolite 2-hydroxyglutarate (2HG), accumulated in gliomas with IDH mutation status, can be detected in vivo using magnetic resonance spectroscopy (MRS). METHODS: The 2HG-MRS technique remains technically challenging. We have summarized the results of the first pilot study in Australia, which included 10 patients affected by glioma. The data recorded from May 2017 to November 2018 were analyzed. RESULTS: In our exploratory study, we reached a sensitivity and specificity of 100%, confirming the strong predictive role of 2HG, as detected using MRS, in the diagnosis of glioma. CONCLUSION: In the present study, we have focused on methodological tips and future perspectives of the technique in the neuroimaging and neuro-oncological scenario. We would advocate the integration of 2HG-MRS into standard clinical practice.

The T2-FLAIR-mismatch sign as an imaging biomarker for IDH and 1p/19q status in diffuse low-grade gliomas: a systematic review with a Bayesian approach to evaluation of diagnostic test performance.

OBJECTIVE: With the revised WHO 2016 classification of brain tumors, there has been increasing interest in imaging biomarkers to predict molecular status and improve the yield of genetic testing for diffuse low-grade gliomas (LGGs). The T2-FLAIR-mismatch sign has been suggested to be a highly specific radiographic marker of isocitrate dehydrogenase (IDH) gene mutation and 1p/19q codeletion status in diffuse LGGs. The presence of T2-FLAIR mismatch indicates a T2-hyperintense lesion that is hypointense on FLAIR with the exception of a hyperintense rim. METHODS: In accordance with PRISMA guidelines, we performed a systematic review of the Ovid Medline, Embase, Scopus, and Cochrane databases for reports of studies evaluating the diagnostic performance of T2-FLAIR mismatch in predicting the IDH and 1p/19q codeletion status in diffuse LGGs. Results were combined into a 2 × 2 format, and the following diagnostic performance parameters were calculated: sensitivity, specificity, positive predictive value, negative predictive value, and positive (LR+) and negative (LR-) likelihood ratios. In addition, we utilized Bayes theorem to calculate posttest probabilities as a function of known pretest probabilities from previous genome-wide association studies and the calculated LRs. Calculations were performed for 1) IDH mutation with 1p/19q codeletion (IDHmut-Codel), 2) IDH mutation without 1p/19q codeletion (IDHmut-Noncodel), 3) IDH mutation overall, and 4) 1p/19q codeletion overall. The QUADAS-2 (revised Quality Assessment of Diagnostic Accuracy Studies) tool was utilized for critical appraisal of included studies. RESULTS: A total of 4 studies were included, with inclusion of 2 separate cohorts from a study reporting testing and validation (n = 746). From pooled analysis of all cohorts, the following values were obtained for each molecular profile-IDHmut-Codel: sensitivity 30%, specificity 73%, LR+ 1.1, LR- 1.0; IDHmut-Noncodel: sensitivity 33.7%, specificity 98.5%, LR+ 22.5, LR- 0.7; IDH: sensitivity 32%, specificity 100%, LR+ 32.1, LR- 0.7; 1p/19q codeletion: sensitivity 0%, specificity 54%, LR+ 0.01, LR- 1.9. Bayes theorem was used to calculate the following posttest probabilities after a positive and negative result, respectively-IDHmut-Codel: 32.2% and 29.4%; IDHmut-Noncodel: 95% and 40%; IDH: 99.2% and 73.5%; 1p/19q codeletion: 0.4% and 35.1%. CONCLUSIONS: The T2-FLAIR-mismatch sign is an insensitive but highly specific marker of IDH mutation but not 1p/19q codeletion in diffuse LGGs, although there may be significant exceptions. These findings support the utility of T2-FLAIR mismatch as an imaging-based biomarker for positive selection of patients with IDH-mutant gliomas.

Increased 14C-acetate accumulation in IDH-mutated human glioblastoma: implications for detecting IDH-mutated glioblastoma with 11C-acetate PET imaging.

PURPOSE: Recently, the potential value of isocitrate dehydrogenase (IDH) mutation as a prognostic marker in glioblastomas has been established. Glioblastomas are classified by their IDH mutation status under the 2016 WHO classification system. However, noninvasive diagnostic methods for the mutation status in glioblastoma patients have not been established so far. The purpose of this study was to evaluate the difference of acetate metabolism between in glioblastomas with wild-type IDH and in those with IDH mutation by comparing the uptake of 14C-acetate using genetically engineered glioblastoma cell lines in vitro and in vivo. METHODS: We established glioblastoma cells (U251) expressing IDH1 R132H and examined the cell uptake of [1-14C]acetate. Biodistribution studies and an autoradiographic study for U251 cell tumor-bearing mice (BALB/c-nu/nu) with or without the IDH1 mutation were performed 1 h after [1-14C]acetate administration. RESULTS: Significantly higher uptake of [1-14C]acetate was observed in U251/IDH1 R132H cells than in U251/IDH1 wild-type cells both in vitro (10.11 ± 0.94 vs. 4.26 ± 0.95%dose/mg, p = 0.0047) and in vivo (0.97 ± 0.14 vs. 0.66 ± 0.05%ID/g; p = 0.0037). Tumor-to-muscle ratios were also significantly higher in U251/IDH1 R132H tumors (3.36 ± 0.41 vs. 1.88 ± 0.59, p = 0.0030). The autoradiographic study shows the entirely higher radioactivity of the U251/IDH1 R132H tumor tissue section than that of the U251/IDH1 Wild-type tumor. CONCLUSIONS: In vitro and in vivo studies demonstrated that the uptake of radiolabeled acetate was significantly higher in IDH-mutated cells than in IDH-wild-type cells.

Lower Grade Gliomas: Relationships Between Metabolic and Structural Imaging with Grading and Molecular Factors.

BACKGROUND: Positron emission tomography (PET) is a valuable tool for the characterization of brain tumors in vivo. However, few studies have investigated the correlation between carbon-11-methionine (11C-METH) PET metrics and the clinical, radiological, histological, and molecular features of patients affected by lower grade gliomas (LGGs). The present observational study evaluated the relationships between 11C-METH PET metrics and structural magnetic resonance imaging (MRI) findings with the histomolecular biomarkers in patients with LGGs who were candidates for surgery. METHODS: We enrolled 96 patients with pathologically proven LGG (51 men, 45 women; age 44.1 ± 13.7 years; 45 with grade II, 51 with grade III), who had been referred from March 2012 to January 2015 for tumor resection and had undergone preoperative 11C-METH PET. The semiquantitative metrics for 11C-METH PET included maximum standardized uptake value (SUVmax), SUV ratio to normal brain, and metabolic tumor burden (MTB). The PET semiquantitative metrics were analyzed and compared with the MRI features, histological diagnosis, isocitrate dehydrogenase-1/2 status, and 1p/19q codeletion. RESULTS: Histological grade was associated with SUVmax (P = 0.002), SUV ratio (P = 0.011), and MTB (P = 0.001), with grade III lesions showing higher values. Among the nonenhancing lesions on MRI, SUVmax (P = 0.001), SUV ratio (P = 0.003) and MTB (P < 0.001) were significantly different statistically for grade II versus grade III. The MRI lesion volume correlated poorly with MTB (r2 = 0.13). The SUVmax and SUV ratio were greater (P < 0.05) in isocitrate dehydrogenase-1/2 wild-type lesions, and the SUV ratio was associated with the presence of the 1p19q codeletion. CONCLUSIONS: The 11C-METH PET metrics correlated significantly with histological grade and the molecular profile. Semiquantitative PET metrics can improve the preoperative evaluation of LGGs and thus support clinical decision-making.

Intraoperative assessment of isocitrate dehydrogenase mutation status in human gliomas using desorption electrospray ionization-mass spectrometry.

OBJECTIVE: The authors describe a rapid intraoperative ambient ionization mass spectrometry (MS) method for determining isocitrate dehydrogenase (IDH) mutation status from glioma tissue biopsies. This method offers new glioma management options and may impact extent of resection goals. Assessment of the IDH mutation is key for accurate glioma diagnosis, particularly for differentiating diffuse glioma from other neoplastic and reactive inflammatory conditions, a challenge for the standard intraoperative diagnostic consultation that relies solely on morphology. METHODS: Banked glioma specimens (n = 37) were analyzed by desorption electrospray ionization-MS (DESI-MS) to develop a diagnostic method to detect the known altered oncometabolite in IDH-mutant gliomas, 2-hydroxyglutarate (2HG). The method was used intraoperatively to analyze tissue smears obtained from glioma patients undergoing resection and to rapidly diagnose IDH mutation status (< 5 minutes). Fifty-one tumor core biopsies from 25 patients (14 wild type [WT] and 11 mutant) were examined and data were analyzed using analysis of variance and receiver operating characteristic curve analysis. RESULTS: The optimized DESI-MS method discriminated between IDH-WT and IDH-mutant gliomas, with an average sensitivity and specificity of 100%. The average normalized DESI-MS 2HG signal was an order of magnitude higher in IDH-mutant glioma than in IDH-WT glioma. The DESI 2HG signal intensities correlated with independently measured 2HG concentrations (R2 = 0.98). In 1 case, an IDH1 R132H-mutant glioma was misdiagnosed as a demyelinating condition by frozen section histology during the intraoperative consultation, and no resection was performed pending the final pathology report. A second craniotomy and tumor resection was performed after the final pathology provided a diagnosis most consistent with an IDH-mutant glioblastoma. During the second craniotomy, high levels of 2HG in the tumor core biopsies were detected. CONCLUSIONS: This study demonstrates the capability to differentiate rapidly between IDH-mutant gliomas and IDH-WT conditions by DESI-MS during tumor resection. DESI-MS analysis of tissue smears is simple and can be easily integrated into the standard intraoperative pathology consultation. This approach may aid in solving differential diagnosis problems associated with low-grade gliomas and could influence intraoperative decisions regarding extent of resection, ultimately improving patient outcome. Research is ongoing to expand the patient cohort, systematically validate the DESI-MS method, and investigate the relationships between 2HG and tumor heterogeneity.

Perfusion MRI grading diffuse gliomas: Impact of permeability parameters on molecular biomarkers and survival.

BACKGROUND AND PURPOSE: Our objectives were: (1) compare dynamic susceptibility-weighted (DSC) and dynamic contrast-enhanced (DCE) permeability parameters, (2) evaluate diagnostic accuracy of DSC and DCE discriminating high- and low-grade tumors, (3) analyze relationship of permeability parameters with overall (OS) and progression-free survival (PFS) and (4) assess differences in high-grade tumors classified according to molecular biomarkers. MATERIALS AND METHODS: 49 patients with histologically proved diffuse gliomas underwent DSC and DCE imaging. Parametric maps of cerebral blood volume (CBV), CBV-leakage corrected, volume transfer coefficient (Ktrans), fractional volume of the extravascular extracellular space (EES) (Ve), fractional blood plasma volume (Vp) and rate constant between EES and blood plasma (Kep) were calculated. High-grade gliomas were also classified according to isocitrate dehydrogenase (IDH), alpha-thalassemia/mental retardation syndrome X-linked (ATRX) and O6-methylguanine-dna-methyltransferase promoter methylation (MGMT) status. RESULTS: There is correlation between parameters leakage, Ktrans and Vp. ROC curve analysis showed significance in both Ktrans and Ve for glioma grading. Threshold value of 0.075 for Ve generated the best combination of sensitivity (80%) and specificity (75%) in tumor gradation. Leakage was the only permeability parameter related to OS (P=0.006) and PFS (0.012); with prolonged survival for leakage values lower than 1.2. IDH-mutated high-grade tumors showed lower leakage and Ktrans values. High-grade tumors with loss of ATRX presented lower leakage and Vp values. CONCLUSIONS: Both DSC and DCE permeability parameters serve as non-invasive method for glioma grading. Leakage was the unique permeability parameter related to survival and the best discriminating high-grade gliomas classified according to IDH and ATRX status.

Conventional MR-based Preoperative Nomograms for Prediction of IDH/1p19q Subtype in Low-Grade Glioma.

RATIONALE AND OBJECTIVES: To develop nomogram models incorporating MR and clinical features for preoperative prediction of isocitrate dehydrogenase (IDH)/1p19q subtype in patients with lower-grade gliomas (LGG). MATERIALS AND METHODS: We classified LGG (149 patients) into three categories: (1) IDH mutation and 1p/19q codeletion, (2) IDH mutation and no 1p/19q codeletion, and (3) wild-type IDH. The correlation between clinical and MR features and IDH/1p19q subtype was analyzed. RESULTS: (1) Multivariate analysis showed that hemorrhage (yes vs no odds ratio [OR]: 12.775), enhancing margin (poorly vs well defined OR: 17.87), and SVZ (SVZ+ vs SVZ- OR: 0.304 were associated with a higher incidence of IDHmut-codel status (All p < 0.05). (2) Multivariate analysis showed that age (≥40 years vs <40 years OR: 0.139), hemorrhage (yes vs no OR: 0.095), enhancing margin (poorly vs well defined OR: 0.275), volume (>60 cm3 vs ≤60 cm3 OR: 5.111), and the shortest distance from the tumor centroid to the edge of the lateral ventricles (CS) (>30 mm vs ≤30 mm OR: 3.766) were associated with a higher incidence of IDHmut-noncodel status. (3) Multivariate analysis showed age (≥40 years vs <40 years OR: 17.311), tumor site (other vs frontal lobe OR: 4.696), volume (>60 cm3 vs ≤60 cm3 OR: 0.188), CS (>30 mm vs ≤30 mm OR: 0.285), necrosis (yes vs no OR: 0.193), and proportion CE tumor (>5% vs ≤5% OR: 5.253) were associated with a higher incidence of IDHwt status. Three nomogram models showed good discrimination (all area under the curve > 0.8) and calibration. CONCLUSION: Clinical and MR features may therefore be used to facilitate the preoperative prediction of LGG IDH/1p19q subtype.

The role of a monoclonal antibody 11C8B1 as a diagnostic marker of IDH2-mutated sinonasal undifferentiated carcinoma.

IDH2 R172 mutations occur in >80% sinonasal undifferentiated carcinomas ("SNUC") and ~80% of these are R172S and R172T variants. We examined the utility of the monoclonal antibody 11C8B1 to IDH2 R172S in IDH2 R172-mutated tumors to establish an immunohistochemistry protocol as a surrogate method for IDH2 R172S mutation detection. Eighty-eight formalin-fixed paraffin-embedded tumors including 42 sinonasal tumors and a variety of IDH1/2-mutated malignancies were tested by immunohistochemistry. The IDH1/2 mutation status was determined in 86 cases by a targeted massively parallel sequencing MSK-IMPACTTM assay. Interestingly, monoclonal antibody 11C8B1 was reactive with all IDH2 R172S (N = 15) mutated tumors including 12 sinonasal carcinomas, 2 high-grade sarcomas and one intrahepatic cholangiocarcinoma, and with all R172T (N = 3) mutated sinonasal carcinomas displaying a distinct granular cytoplasmic labeling in all R172S/T mutated malignancies. 11C8B1 immunohistochemistry was also positive in 2 of 6 IDH1 R132S-mutated tumors, including one intrahepatic cholangiocarcinoma and one chondrosarcoma showing a smooth homogeneous cytoplasmic staining pattern. All IDH2 R172G/K/M/W (N = 22) and IDH1 132H/C/G/L (N = 15) mutated tumors, and all IDH1/2-wild-type tumors (N = 25), including a histologic variety of 23 sinonasal tumors, were immunonegative. Importantly, 11 sinonasal undifferentiated carcinomas (N = 14, 79%) and 3 (100%) high-grade neuroendocrine carcinomas, large cell type were 11C8B1 immunopositive. Literature search revealed a virtual absence of IDH2 R172 and IDH1 R132S mutations in >1000 cases of 8 different malignancies included in the differential diagnosis of sinonasal undifferentiated carcinoma. Our study suggests that positive IDH2 11C8B1 immunohistochemistry in sinonasal carcinomas would be highly predictive of the presence of IDH2 R172S/T mutations and could serve as a reliable adjunct diagnostic marker of sinonasal undifferentiated carcinomas in >70% cases.

Current and future tools for determination and monitoring of isocitrate dehydrogenase status in gliomas.

PURPOSE OF REVIEW: Hotspot mutations of isocitrate dehydrogenase 1 (R132) or 2 (R172) genes affect 40% of diffuse gliomas, mostly grades II and III. The mutant enzyme produces high quantities of d-2-hydroxyglutarate (D2HG), which reshapes the epigenetic of the cell leading to gliomagenesis. For the clinician, the isocitrate dehydrogenase (IDH) mutation is a major biomarker with diagnostic, prognostic, and predictive consequences. With the development of specific inhibitors and vaccination, it appears also a potential actionable target. RECENT FINDINGS: IDH status is routinely determined on tumor sample by sequencing and immunohistochemistry detecting the most common mutant protein (IDH1R132H). Recently noninvasive diagnostic approaches have been developed based on the detection of the mutant DNA or the D2HG in body fluids, and the detection of D2HG by magnetic resonance spectroscopy of the brain. SUMMARY: These new techniques open avenues for non invasive diagnostic of glioma in patients not amenable to biopsy, in the preoperative setting and also duringpatients follow-up for evaluation of treatment response and prediction of recurrence.