Diagnosis Of Diffuse Gliomas Research Articles

PATH-05. PRIMARY AND SECONDARY GLIOSARCOMA: RADIOLOGICAL AND PROGNOSTIC DIFFERENCES USING COMPREHENSIVE MULTI-OMICS ANALYSIS

Abstract Purpose Gliosarcoma (GS), a rare variant of glioblastoma (GB), is further classified into primary (de novo) gliosarcoma (PGS), and secondary gliosarcoma (SGS), which is defined as recurrence after a diagnosis of diffuse glioma. Poorer survival of SGS than PGS has been reported, however, the detailed mechanism remains unknown. METHODS: A retrospective retrieval of pathological confirmed GS was performed. All the clinical, radiological, and pathological comparisons were based on the diagnosis of GS. A multi-omics, including whole exome sequencing, transcriptome, proteome and phosphoproteome, approach was used to acquire the molecular profiles of these specimens. RESULTS: From 2003 to 2020, a total of 28 GSs were identified, including 19 PGSs and 9 SGSs. The age tended to be younger in SGS group than PGS group (52.1 ± 10.9 vs. 60.8 ± 11.5, p=0.069). SGSs tended to present with dural attachment (p=0.071) and were significantly associated with major vessel encasement (p=0.002) than PGSs. The Ki-67 index tended to be higher in SGSs than PGSs (p=0.081). The GS survival was significantly shorter in SGS group than PGS group (median: 7.9 vs. 32.4 months, p< 0.001). The multi-omics analysis demonstrated SGSs had significantly higher expression of negative regulation of megakaryocyte differentiation, telomere capping, and DNA replication nucleosome assembly pathways than PGSs. Next, using proteome / phosphoproteome nonnegative matrix factorization analysis, PGS was categorized into two clusters (PGS_C1 versus PGS_C2) with distinct multi-omics features. Of which, PGS_C1 (n=4) tended to have shorter survival than PGS_C2 (n=15, p=0.054). Notably, the survival of patients in PGS_C1, who had similar multi-omics signature to SGS, were as poor as those of SGSs. CONCLUSIONS: In summary, this study provides, for the first time, in depth evidence for understanding GS and presents multi-omics biomarkers with prognostic significance. Further therapeutic translation should based on current findings to benefit GS patients.

Overview of The Current Histopathologic and Molecular Techniques Used in Diagnosis of Diffuse Glioma

Overview of The Current Histopathologic and Molecular Techniques Used in Diagnosis of Diffuse Glioma

OS02.6.A Lacosamide in monotherapy in brain tumour-related epilepsy (BTRE): results from an Italian multicentre retrospective study

Abstract Background Lacosamide (LCM) is a third-generation anti-seizure medication (ASM) approved for focal onset epilepsy in patients aged ≥4 years. Previous studies have reported an efficacy of LCM as add-on treatment in brain tumour-related epilepsy (BTRE). To date, there are no studies in the literature focusing on lacosamide used in monotherapy to treat BTRE. In our retrospective study we investigated efficacy and tolerability of LCM in monotherapy in a multicentre national cohort of primary brain tumour patients. Patients and Methods Adult patients who were treated with LCM in monotherapy were collected from 12 Italian Centres (either mainly involved in neuro-oncology or in epileptology). Main inclusion criteria were diagnosis of primary brain tumour; at least two focal-onset seizures in the disease course; LCM used either as primary or secondary monotherapy after withdrawal of previous ASMs. For each patient, we evaluated seizure freedom at 3 and 6 months (primary endpoints), side effects and drop-out rate (secondary endpoints). Results We collected 132 patients. The majority of patients had a diagnosis of diffuse gliomas, being those with lower-grade glioma 66 (50.0%) and those with glioblastoma 33 (25.0%). Overall, LCM led to seizure-freedom in 64.4% of patients at 3 months and 55% at 6 months. Patients who used two or more ASMs before LCM had a worse seizure control than patients in monotherapy with LCM as first choice.In 14 patients, we observed seizure control despite tumour progression on magnetic resonance (MRI). Multivariate analysis showed that gross-total resection at diagnosis and use of steroids were significantly associated with higher seizure freedom rate at 6 months. Side effects were mainly mild (grade 1-2 according to the CTCAE classification), and the drop-out rate was low (1.5%). The main side effects were dizziness and somnolence. Conclusion This is the first study on the role of LCM in monotherapy in BTRE. The study has shown a good efficacy and tolerability of LCM with more than a half of patients becoming seizure-free at 6 months and with a very low rate of drop-out. Further studies are needed to confirm these preliminary data in a prospective manner, adding quality of life and neurocognitive functions as endpoints.

Reclassification of Mongolian Diffuse Gliomas According to the Revised 2016 World Health Organization Central Nervous System Tumor Classification.

BackgroundThe 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors has been modified to incorporate the IDH mutation and 1p/19q co-deletion in the diagnosis of diffuse gliomas. In this study, we aimed to evaluate the feasibility and prognostic significance of the revised 2016 WHO classification of CNS tumors in Mongolian patients with diffuse gliomas.MethodsA total of 124 cases of diffuse gliomas were collected, and tissue microarray blocks were made. IDH1 mutation was tested using immunohistochemistry, and 1p/19q co-deletion status was examined using fluorescence in situ hybridization analysis.ResultsAccording to the 2016 WHO classification, 124 cases of diffuse brain glioma were reclassified as follows: 10 oligodendroglioma, IDHmut and 1p/19q co-deleted; three anaplastic oligodendroglioma, IDHmut and 1p/19q co-deleted; 35 diffuse astrocytoma, IDHmut, 11 diffuse astrocytoma, IDHwt, not otherwise specified (NOS); 22 anaplastic astrocytoma, IDHmut, eight anaplastic astrocytoma, IDHwt, NOS; and 35 glioblastoma, IDHwt, NOS, respectively. The 2016 WHO classification presented better prognostic value for overall survival in patients with grade II tumors than traditional histological classification. Among patients with grade II tumors, those with oligodendroglioma IDHmut and 1p/19q co-deleted and diffuse astrocytoma IDHmut showed significantly higher survival than those with diffuse astrocytoma IDHwt, NOS (p<.01).ConclusionsMongolian diffuse gliomas could be reclassified according to the new 2016 WHO classification. Reclassification revealed substantial changes in diagnosis of both oligodendroglial and astrocytic entities. We have confirmed that the revised 2016 WHO CNS tumor classification has prognostic significance in Mongolian patients with diffuse gliomas, especially those with grade II tumors.

Qualitative and Quantitative Analysis of IDH1 Mutation in Progressive Gliomas by Allele-Specific qPCR and Western Blot Analysis.

To date, diagnosis of IDH1 mutation is based on DNA sequencing and immunohistochemistry, methods limited in terms of sensitivity and ease of use. Recently, the diagnosis of IDH1 mutation by real-time polymerase chain reaction was introduced as an alternative method. In this study, real-time polymerase chain reaction was validated as a tool for detection of IDH1 mutation, and expression levels were analyzed for correlation with course of the disease. A total of 113 tumor samples were obtained intraoperatively from 84 patients with glioma having a diagnosis of diffuse glioma (World Health Organization II), anaplastic glioma (World Health Organization III), secondary glioblastoma ± chemotherapy, primary glioblastoma ± chemotherapy (World Health Organization IV). Tumor samples were snap frozen and processed for sectioning and RNA and protein isolation. Presence of IDH1 mutation was determined by DNA sequencing. Hereafter, quantitative expression of IDH1 messenger RNA was assessed using real-time polymerase chain reaction with specific primers for IDH1 mutation and –wt; protein expression was verified by Western Blot analysis and immunohistochemistry. Additionally, 19 samples of low-grade glioma and their consecutive high-grade glioma were analyzed at different time points of the disease. IDH1 mutation was identified in 63% of samples by DNA sequencing. In correlation with the real-time polymerase chain reaction results, a cutoff value was determined. Above this threshold, sensitivity and specificity of real-time polymerase chain reaction in detecting IDH1 mutation were 98% and 94%, respectively. Quantitative analysis revealed that IDH1 mutation expression is upregulated in secondary glioblastoma (mean ± standard error of mean: 3.52 ± 0.55) compared to lower grade glioma (II = 1.54 ± 0.22; III = 1.67 ± 0.23). In contrast, IDH1 wt expression is upregulated in all glioma grades (concentration >0.1) compared to control brain tissue (0.007 ± 0.0016). Western Blot analysis showed a high concordance to both sequencing and real-time polymerase chain reaction results in qualitative analysis of IDH1 mutation status (specificity 100% and sensitivity 100%). Moreover, semiquantitative protein expression analysis also showed higher expression levels of mutated IDH1 in secondary glioblastoma. In our study, real-time polymerase chain reaction and Western Blot analysis were found to be highly efficient methods in detecting IDH1 mutation in glioma samples. As cost-effective and time-saving methods, real-time polymerase chain reaction and Western Blot analysis may therefore play an important role in IDH1 mutation analysis in the future. IDH1 mutation expression level was found to correlate with the course of disease to a certain extent. Yet, clinical factors as recurrent disease or prior radiochemotherapy did not alter IDH1 mutation expression level.

Abstract 2218: Qualitative and quantitative analysis of IDH1 mutation in progressive gliomas by allele-specific quantitative RT-PCR and Western blot analysis

Abstract Diagnostic of the IDH1 mutation (IDH1mut) is so far based on DNA sequencing and immunohistochemistry (IHC), methods limited in terms of sensitivity and ease of use. Recently, measuring the IDH1mut level by real time PCR was introduced as alternative method. Therefore, we aimed to (i) validate this new technique in a larger patient cohort, compare it to control tissue, and (ii) investigate if the expression of both, IDH1mut and IDH1 wildtype (IDH1wt) correlates with the course of disease and different treatment regimens. A total of 113 tumor samples were obtained intraoperatively from 84 glioma patients with diagnosis of diffuse glioma (WHO°II), anaplastic glioma (WHO°III), secondary glioblastoma +/- chemotherapy (CTx), primary glioblastoma +/- CTx (WHO°IV). Tumor samples were snap frozen and processed for sectioning, RNA and protein isolation. The quantitative expression of IDH1 mRNA was assessed using real-time PCR with specific primers for IDH1mut and -wt; protein expression was verified by Western Blot analysis and IHC. Additionally, 19 samples of LGG and their consecutive HGG were analyzed at different time points of disease. Allele-specific quantitative RT-PCR does work in larger patient cohorts and seems to be an easy and ∼10 times more sensitive method for quantitative IDH1mut evaluation compared to the ones used so far. Our results with this new method confirmed previous data showing that most astrocytomas and secondary GBM bear the mutation (conc. 0.13 to 0.2) whereas most primary GBM do not (conc. ∼0.025). Quantitative analysis revealed that IDH1mut expression is upregulated in sGBM (mean±SEM: 3.52±0.55) compared to lower grade glioma (II° = 1.54±0.22; III° = 1.67±0.23). By contrast, IDH1wt expression is upregulated in all glioma grades (con. &amp;gt;0.1) compared to control brain tissue (0.007± 0.0016). Western Blot analysis showed a high concordance to both, sequencing and RT-PCR results in qualitative analysis of IDH1mut status (specificity 100% and sensitivity 100%). Moreover, semiquantitative protein expression analysis also showed higher expression levels of mutated IDH1 in sGBM. Taken together, recurrent disease and radiochemotherapy do not alter the general IDH1 status. Moreover, we found an increase of IDH1mut gene expression in sec. GBM compared to lower grade glioma indicating a pivotal role of IDH1mut not only in gliomagenesis but also in glioma progression. Citation Format: Marco Timmer, Moritz Perrech, Gabriele Röhn, Lena Dreher, Roland Goldbrunner. Qualitative and quantitative analysis of IDH1 mutation in progressive gliomas by allele-specific quantitative RT-PCR and Western blot analysis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2218. doi:10.1158/1538-7445.AM2015-2218

MOLECULAR-GUIDED NEOADJUVANT APPROACH FOR CHEMOSENSITIVE GLIOMAS

BACKGROUND: Brain is the very organ where functional preservation is critical, however, neoadjuvant chemotherapy (NAC) has not yet been systematically applied into the treatment of glial tumors. METHODS: Since February 2006, treatment for gliomas at Keio University Hospital has been tailored by molecular guidance: grade II-III gliomas with 1p19q codeletion or MGMT methylation have been treated by upfront chemotherapy, and the second surgery was planned after tumor volume reduction by NAC in the cases in which initial surgery was incomplete. The study includes the consecutive patients who fulfilled the following criteria: a) histopathological diagnosis of diffuse glioma of WHO grade II or III; b) no or scant contrast-enhancement; c) 1p19q codeletion or promoter methylation of the MGMT gene; d) written informed consent. RESULTS: Twenty gliomas (grade II: 17, grade III: 3) suggested to be responsive to chemotherapy have been treated by the neoadjuvant strategy. Curiously, the majority of gliomas referred to our hospital invaded into the eloquent areas, and the particular patient cohort provided the unique opportunity to see the true chemotherapeutic response. CR/PR/MR was in 9/18 evaluable cases, and there was no PD within 6 months. Importantly, the second-look removal after tumor volume reduction was performed in 12/17 incompletely resected tumors. CONCLUSIONS: NAC according to molecular guidance could often produce significant volume reduction of the incompletely resected gliomas. For chemosensitive low-grade gliomas, the upfront chemotherapy might hold optional advantages over upfront radiotherapy: radiotherapy can be saved for later malignant transformation; tumor volume reduction by NAC could provide the chance of radical resection that is not initially possible. SECONDARY CATEGORY: Neuropathology & Tumor Biomarkers.

Correlation between magnetic resonance imaging findings and histological diagnosis of intrinsic brainstem lesions in adults

Management of brainstem mass lesions remains a controversial issue, especially when the lesion cannot be excised and when infiltration occurs; moreover, the benefits of a stereotactic procedure are still under debate. In most studies, treatment decisions are based solely on MRI features and do not include a histopathological diagnosis. In the current study, we compared MRI characteristics with histopathological findings of intrinsic brainstem lesions and identified the characteristics associated with the diagnosis of pathologies other than diffuse glioma. From February 1988 through August 2007, 96 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, on adult patients with intrinsic brainstem lesions not amenable to excision. Of the 96 patients, 42 were women and 54 were men, with a mean age of 41 years (range, 18-75 years). Data analysis of the MRI findings revealed focal (P < .05) and contrast enhancing lesions (P < .05), and these lesions were significant factors associated with the diagnosis of pathologies other than diffuse glioma. Focal lesions were a significant factor associated with a diagnosis of nontumor lesions (P < .05). In conclusion, the diagnostic effect of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with focal or enhancing lesions shown by MRI, in whom the diagnosis of diffuse glioma was less frequent.

Correlation among magnetic resonance imaging findings, prognostic factors for survival, and histological diagnosis of intrinsic brainstem lesions in children

The aim of this study was to compare MR imaging characteristics with histopathological findings of intrinsic brainstem lesions and also to show the prognostic factors in patients with diffuse brainstem glioma. Between February 1988 and August 2007, 44 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, in children with intrinsic brainstem lesions not amenable to excision. Twenty-six were female and 18 male, and the mean age was 6 years. Histological evaluation revealed diffuse brainstem glioma in all patients with diffuse nonenhancing brainstem lesions. Diffuse brainstem glioma was found in 18 patients (90%) with diffuse enhancing brainstem lesions. Pathological entities different from diffuse glioma were verified in 2 patients (10%)-1 with ependymoma and 1 with ganglioglioma. In 4 of 5 patients with a focal nonenhancing brainstem lesion, the histopathological diagnosis was diffuse low-grade glioma. In 6 of 10 patients with focal enhancing brainstem lesion, the diagnosis was diffuse brainstem glioma, and pathological entities different from diffuse brainstem glioma were verified in 2 (20%), both with pilocytic astrocytoma. The mean 1-year actuarial survival rates for patients classified with low-grade and high-grade glioma were 80.4% ± 0.08% and 48.6% ± 0.14%, respectively. The impact of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with MR imaging-documented enhancing lesions in whom the diagnosis of diffuse glioma was less frequent. Patients with low-grade glioma seem to have longer survival than those with high-grade glioma.

Focal cortical dysplasia coexisting with diffuse astrocytoma in childhood: A case report and reappraisal of the glial component in archival FCD cases

We report a rare case of focal cortical dysplasia (FCD) concurring with diffuse astrocytoma and arachnoid cyst, and also re-evaluate the glial component in archival FCD cases for the differential diagnosis of diffuse gliomas. A 7-year-old boy with a 9-month history of psychomotor seizures disclosed a hyperintense area accompanied by a cystic lesion in the left temporal lobe on MRI. The surgical specimen displayed dyslamination of the cortices and ectopic neurons in the white matter, associated with dysmorphic neurons, indicating FCD type IIA. Additionally, the lesion showed diffuse proliferation and infiltration of glial cells, immunopositive for infiltrating glioma markers (nestin, doublecortin, MAP-2e) and p53, and MIB-1 index was 2.0%. These findings indicated coexisting diffuse astrocytoma. Coexistence of diffuse glioma with FCD is unusual, but we often notice increased population of small glial cells in FCD lesions. Re-evaluation of archival FCD cases with diverse markers revealed that reactive microglia significantly proliferate in the white matter lesions. Therefore, a careful pathological assessment has to be made to define a rare case of diffuse glioma occurring in FCD.

Clarifying the Diffuse Gliomas

Diffuse gliomas are the most common brain tumors and include astrocytomas, oligodendrogliomas, and oligoastrocytomas. Their correct pathologic diagnosis requires the ability to distinguish astrocytic from oligodendroglial differentiation in histologic sections, a challenging feat even for the most experienced neuropathologist. Interobserver variability in the diagnosis of diffuse gliomas has been high owing to subjective diagnostic criteria, overlapping morphologic features, and variations in training and practice among pathologists. A select, albeit imperfect, group of molecular and immunohistochemical tests are available to assist in diagnosis of these lesions. Combined loss of chromosomes 1p and 19q is a genetic signature of oligodendrogliomas, whereas gains of chromosome 7 in the setting of intact 1p/19q are more typical of astrocytomas. Detection of amplified epidermal growth factor receptor favors the diagnosis of high-grade astrocytomas over anaplastic oligodendroglioma, which is especially relevant for small cell astrocytomas. Strong nuclear staining for p53 often reflects TP53 mutation and is typical of low-grade astrocytomas. The Olig family of transcription factors has not demonstrated their diagnostic usefulness. Diffuse gliomas remain a diagnostic challenge, and new markers are needed for proper classification and directed therapies.

Clarifying the Diffuse Gliomas

Diffuse gliomas are the most common brain tumors and include astrocytomas, oligodendrogliomas, and oligoastrocytomas. Their correct pathologic diagnosis requires the ability to distinguish astrocytic from oligodendroglial differentiation in histologic sections, a challenging feat even for the most experienced neuropathologist. Interobserver variability in the diagnosis of diffuse gliomas has been high owing to subjective diagnostic criteria, overlapping morphologic features, and variations in training and practice among pathologists. A select, albeit imperfect, group of molecular and immunohistochemical tests are available to assist in diagnosis of these lesions. Combined loss of chromosomes 1p and 19q is a genetic signature of oligodendrogliomas, whereas gains of chromosome 7 in the setting of intact 1p/19q are more typical of astrocytomas. Detection of amplified epidermal growth factor receptor favors the diagnosis of high-grade astrocytomas over anaplastic oligodendroglioma, which is especially relevant for small cell astrocytomas. Strong nuclear staining for p53 often reflects TP53 mutation and is typical of low-grade astrocytomas. The Olig family of transcription factors has not demonstrated their diagnostic usefulness. Diffuse gliomas remain a diagnostic challenge, and new markers are needed for proper classification and directed therapies.