Malignant transformation-related genes in meningiomas: allelic loss on 1p36 and methylation status of p73 and RASSF1A

2007 ◽  
Vol 107 (2) ◽  
pp. 398-404 ◽  
Author(s):  
Yukimi Nakane ◽  
Atsushi Natsume ◽  
Toshihiko Wakabayashi ◽  
Sachie Oi ◽  
Motokazu Ito ◽  
...  
Keyword(s):  
Malignant Transformation ◽  
Promoter Methylation ◽  
Methylation Status ◽  
Genetic Alterations ◽  
Allelic Loss ◽  
Lower Grade ◽  
Who Grade ◽  
Genetic Fingerprint ◽  
I 11 ◽  
Grade Ii

Object Analysis of meningiomas supports the suggestion that loss of heterozygosity (LOH) of chromosome arm 1p plays an important role in malignancy. The aim of this study was to identify genes related to meningioma progression from the benign state to the atypical and anaplastic states by examining 1p LOH and the promoter methylation of RASSF1A and p73. Methods The authors studied 40 surgical specimens (22 WHO Grade I, 11 Grade II, and seven Grade III) obtained in 37 patients with meningioma. The LOH at 1p36 was analyzed using microsatellite markers, and promoter methylation of p73 and RASSF1A was analyzed using methylation-specific polymerase chain reaction. Results No 1p LOH was detected in the Grade I tumors, whereas it was detected in more than 80% of the Grade II and III tumors. Methylation of the p73 promoter was observed in 81.8 and 71.4% of the Grade II and III tumors, respectively, but it was not observed in any of the Grade I tumors; methylation of the RASSF1A promoter was observed in 18.2, 63.6, and 42.9% of the Grade I, II, and III tumors, respectively. Interestingly, 1p LOH and p73 promoter hyper-methylation were detected in the malignantly transformed tumors but not in the lower-grade primary ones. Conclusions Based on the hypothesis that meningiomas cumulatively acquire genetic alterations and thus progress from the benign to the atypical and anaplastic states, genetic alterations in the methylation status of p73 or RASSF1A along with 1p LOH may result in the malignant transformation of a meningioma. This type of genetic fingerprint may play both diagnostic and therapeutic roles.

scholarly journals Risk of Venous Thromboembolism in Grade II-IV Gliomas as a Function of Molecular Subtype

Neurology ◽  
2020 ◽  
pp. 10.1212/WNL.0000000000011414
Author(s):  
Maria Diaz ◽  
Jasmin Jo ◽  
Mark Smolkin ◽  
Sarah Jane Ratcliffe ◽  
David Schiff
Keyword(s):  
Venous Thromboembolism ◽  
Promoter Methylation ◽  
Cumulative Incidence ◽  
Molecular Subtype ◽  
Methylation Status ◽  
World Health ◽  
Molecular Testing ◽  
Lower Grade ◽  
Idh Mutation ◽  
Grade Ii

Objective:To determine the incidence of venous thromboembolism (VTE) in lower-grade gliomas (LGG, World Health Organization (WHO) grades II-III) and to stratify the risk of VTE by molecular subtype in gliomas grade II-IV, we performed a retrospective review of a large cohort of glioma patients.Methods:We performed a retrospective analysis of a cohort of 635 adult glioma patients with molecular testing seen at the University of Virginia with a diagnosis of glioma established from January 2005 to August 2017. Estimates of cumulative incidence of VTE were calculated with death as competing risk; significance was determined using the Fine and Gray model.Results:Of 256 LGG patients, 81 were isocitrate dehydrogenase (IDH) wild-type; 113 IDH mutant, 1p/19q codeleted; and 62 IDH mutant, 1p/19q intact. With a median follow-up of 17.9 months, the overall cumulative incidence of VTE was 8.2% for grade II (147 patients), 9.2% for grade III (109 patients), and 30.5% for grade IV (334 patients). In grade II-IV patients, absence of an IDH mutation was associated with a three-fold increase in VTE risk when compared to IDH-mutant patients (HR=3.06, 95% CI=2.03-4.64). In GBM patients, there was no difference in VTE incidence according to O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status.Conclusion:Patients with LGG have a higher VTE risk compared to the general population, which is decreased, but not eliminated, in the presence of an IDH mutation. MGMT promoter methylation in GBM does not affect the incidence of VTE.

scholarly journals P14.23 Risk of venous thromboembolism (VTE) in grade II-IV gliomas as a function of molecular subtype

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii71-iii72
Author(s):  
M Diaz ◽  
J Jo ◽  
D Schiff
Keyword(s):  
Molecular Subtype ◽  
Methylation Status ◽  
Promoter Hypermethylation ◽  
Molecular Testing ◽  
Lower Grade ◽  
Idh Mutation ◽  
Mgmt Methylation ◽  
Who Grade ◽  
Grade Ii ◽  
Grade Iii

Abstract BACKGROUND VTE affects up to 30% of patients with glioblastoma (GBM, WHO grade IV), but little is known about its incidence in lower-grade gliomas (LGG, WHO grade II-III). It has been suggested that isocitrate dehydrogenase (IDH) mutation status dramatically decreases the incidence of VTE in glioma patients, through a combination of F3 promoter hypermethylation leading to lower expression of the procoagulant protein tissue factor, and an increased production of D-2-hydroxyglutarate, which has anticoagulant properties (Unruh et al, 2016). Our objective was to determine the incidence of VTE in LGG and stratify VTE risk by molecular subtype in gliomas grade II-IV. MATERIAL AND METHODS We performed a retrospective analysis of 590 glioma patients with molecular testing seen at our institution (UVa) from January 2005 to August 2017. We divided LGG patients into 3 groups: IDH-wildtype (IDHwt); IDH-mutant (IDHmt), 1p/19q-codeleted; and IDHmt, 1p/19q-intact. GBM patients were divided according to MGMT methylation status. Estimates of cumulative incidence of VTE were calculated with death as competing risk, and significance testing was determined using the Fine and Gray model. RESULTS Of 256 LGG patients (147 grade II and 109 grade III), 81 were IDHwt, 113 IDHmt and 1p/19q-codeleted, and 62 IDHmt and 1p/19q-intact. There were 334 GBM patients, with MGMT methylation status available in 263 (98 (37%) methylated and 165 (63%) unmethylated). With a median follow-up of 545 days, the overall incidence of VTE was 8.2% for grade II, 9.2% for grade III and 30.5% for grade IV. The 6-, 12- and 24-month VTE incidence was 4.1%, 4.8% and 5.4% respectively for grade II, 4.6%, 7.3% and 9.2% for grade III and 23.1%, 26.6% and 29% for grade IV. In LGG patients, VTE incidence was slightly higher in IDHwt tumors (11.1%) vs IDHmt, 1p/19q-codeleted (8.8%) and IDHmt, 1p/19q-intact tumors (4.8%). However, this difference was not statistically significant (IDHwt vs IDHmt, 1p/19q-codeleted, sub-distribution hazard ratio (SHR)=1.67, 95% CI=0.59–4.72; IDHwt vs IDHmt, 1p/19q-intact, SHR=1.87, 95% CI=0.54–6.53). In GBM patients, there was no difference in the VTE incidence according to MGMT methylation status (SHR=0.99, 95% CI=0.64–1.54). CONCLUSION In our cohort, the risk of VTE in GBM patients was consistent with historical data; patients with LGG also had a higher VTE risk compared to the general population. In contrast to other retrospective studies in which the incidence of VTE for grade II-IV IDHmt gliomas was 0% (Unruh et al, 2016; Nazari et al, 2018), our data suggest that VTEs do occur in IDHmt LGG patients, although at a lower rate than in IDHwt. MGMT methylation does not seem to influence the incidence of VTE. VTE risk stratification in GBM patients based on IDH mutation is forthcoming.

Quantitative analysis of 06-methylguanine-DNA methyltransferase (MGMT) promoter methylation in patients with low-grade gliomas

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 2069-2069
Author(s):  
A. F. Ochsenbein ◽  
A. D. Schubert ◽  
E. Vassella ◽  
L. Mariani
Keyword(s):  
Promoter Methylation ◽  
Tumor Response ◽  
Methylation Status ◽  
Mgmt Promoter Methylation ◽  
Low Grade ◽  
Who Grade ◽  
Low Grade Gliomas ◽  
Response To Chemotherapy ◽  
Mgmt Promoter ◽  
Grade Ii

2069 Background: Loss of heterozygosity (LOH) on the chromosomes 1p and 19q is associated with sensitivity to alkylating agents like temozolomide (TMZ) in patients with low-grade gliomas; whether methylation of the MGMT-promoter, a predictive factor in glioblastoma patients, also correlates with tumor response to TMZ in low-grade gliomas is unclear. Methods: We performed a retrospective analysis of patients with histologically verified low-grade gliomas (WHO Grade II) who were treated with TMZ for tumor progression at our hospital between November 1999 and November 2007. Objective tumor response was assessed by MRI at 6-month intervals. LOH of microsatellite markers on chromosomes 1p and 19q was determined by polymerase chain reaction (PCR) amplification of the matched pairs of blood and tumor DNA. A methylation-specific, primer extension based PCR method was developed to quanitatively assess the MGMT methylation status in the tumour tissue. Results: Twenty-two patients with a median age of 53 years (range 27–72) were included in the study; 59% were male. Seven patients had prior surgical resection of the tumor. Histological classification revealed 10 oligodendrogliomas, 7 oligoastrocytomas, and 5 astrocytomas. All patients were treated with TMZ 200mg/m2 day1–5 in a 4 wk cycle. Grade 3–4 hematological toxicity occurred in 32% of the patients (9% leucopenia, 23% thrombocytopenia). The progression free survival was 32 months. Combined LOH 1p and 19q was found in 14 pts; 1 patient had LOH 1p alone and 1 patient LOH 19q alone. The LOH status could not be determined in two patients and was normal in the remaining four. MGMT promoter methylation was detectable in 20 pts by conventional PCR and quantitative analysis revealed a methylation status between 12%-100%. The volumetric response to chemotherapy analyzed after 6 months by MRI correlated with the level of MGMT promoter methylation (p = 0.012). Conclusions: Quantitative methylation-specific PCR of the MGMT promoter correlates with radiological response to chemotherapy with temozolomide in WHO grade II gliomas. No significant financial relationships to disclose.

scholarly journals The Expression of Progesterone Receptors in Meningiomas of Different Grades

2019 ◽  
Vol 8 (2) ◽  
pp. 65-69
Author(s):  
Mohammad Tahir ◽  
Tehreem Atif ◽  
Summaya Sohail ◽  
Arfa Nawazish ◽  
Huma Mushtaq
Keyword(s):  
Progesterone Receptor ◽  
Treatment Options ◽  
Progesterone Receptors ◽  
Lower Grade ◽  
Immunoperoxidase Method ◽  
Nuclear Staining ◽  
Who Grade ◽  
Grade Ii ◽  
Who Grade Iii ◽  
Grade Iii

Background: Meningiomas are slow growing intracranial and intraspinal neoplasms with a tendency to recur locally. WHO grades them as I (benign), II (atypical) and III (anaplastic) in order of their increasing aggressiveness, based on histological parameters and brain parenchymal invasion. Progesterone receptors (PR) are more prevalent amongst the lower grade meningiomas. The objective of this study was to determine the immunohistochemical expression of progesterone receptors in meningiomas of different grades.Material and Methods: A total of 100 cases were selected over a period of 2.5 years. Three to five microns’ thick sections stained with Hematoxylin and Eosin were examined microscopically by a team of two Histopathologists and graded into grades I, II and III, according to 2016 WHO classification criteria. Another section of the original tumor was stained with progesterone receptor antibody using the conventional immunoperoxidase method. Stained slides were than examined by the same team of Histopathologists and declared positive (if nuclear staining was observed in more than 10% of tumor cells) or negative. Statistical analysis was done using SPSS version 21.Results: Out of a total of 100 cases of meningioma, there were 79 cases of benign/typical WHO grade I, 15 cases of atypical/ WHO grade II and 6 cases of anaplastic/ WHO grade III tumor. PR status was positive in 89.8 % (71/79) of grade I meningiomas and 46.6 % (7/15) of grade II/Atypical meningiomas. The 06 cases of Anaplastic/WHO grade III tumors were negative for PR. There was a higher prevalence of Progesterone receptors in female patients (89.8%; 53/59) as compared to male meningioma patients (60.9%; 25/41).Conclusion: We observed a decreased expression of progesterone receptor in higher grades of meningioma in this study. It is an effort to explore conservative treatment options for inoperable lesions, as anti-progesterone therapy may hold a promise as a new treatment option in the near future.

scholarly journals Huge heterogeneity in survival in a subset of adult patients with resected, wild-type isocitrate dehydrogenase status, WHO grade II astrocytomas

2019 ◽  
Vol 130 (4) ◽  
pp. 1289-1298 ◽  
Author(s):  
Gaëtan Poulen ◽  
Catherine Gozé ◽  
Valérie Rigau ◽  
Hugues Duffau
Keyword(s):  
Radiation Therapy ◽  
Malignant Transformation ◽  
Isocitrate Dehydrogenase ◽  
Adult Patients ◽  
World Health ◽  
Wild Type ◽  
Who Grade ◽  
Grade Ii ◽  
The Individual

OBJECTIVEWorld Health Organization grade II gliomas are infiltrating tumors that inexorably progress to a higher grade of malignancy. However, the time to malignant transformation is quite unpredictable at the individual patient level. A wild-type isocitrate dehydrogenase (IDH-wt) molecular profile has been reported as a poor prognostic factor, with more rapid progression and a shorter survival compared with IDH-mutant tumors. Here, the oncological outcomes of a series of adult patients with IDH-wt, diffuse, WHO grade II astrocytomas (AII) who underwent resection without early adjuvant therapy were investigated.METHODSA retrospective review of patients extracted from a prospective database who underwent resection between 2007 and 2013 for histopathologically confirmed, IDH-wt, non–1p19q codeleted AII was performed. All patients had a minimum follow-up period of 2 years. Information regarding clinical, radiographic, and surgical results and survival were collected and analyzed.RESULTSThirty-one consecutive patients (18 men and 13 women, median age 39.6 years) were included in this study. The preoperative median tumor volume was 54 cm3 (range 3.5–180 cm3). The median growth rate, measured as the velocity of diametric expansion, was 2.45 mm/year. The median residual volume after surgery was 4.2 cm3 (range 0–30 cm3) with a median volumetric extent of resection of 93.97% (8 patients had a total or supratotal resection). No patient experienced permanent neurological deficits after surgery, and all patients resumed a normal life. No immediate postoperative chemotherapy or radiation therapy was given. The median clinical follow-up duration from diagnosis was 74 months (range 27–157 months). In this follow-up period, 18 patients received delayed chemotherapy and/or radiotherapy for tumor progression. Five patients (16%) died at a median time from radiological diagnosis of 3.5 years (range 2.6–4.5 years). Survival from diagnosis was 77.27% at 5 years. None of the 21 patients with a long-term follow-up greater than 5 years have died. There were no significant differences between the clinical, radiological, or molecular characteristics of the survivors relative to the patients who died.CONCLUSIONSHuge heterogeneity in the survival data for a subset of 31 patients with resected IDH-wt AII tumors was observed. These findings suggest that IDH mutation status alone is not sufficient to predict risk of malignant transformation and survival at the individual level. Therefore, the therapeutic management of AII tumors, in particular the decision to administer early adjuvant chemotherapy and/or radiation therapy following surgery, should not solely rely on routine molecular markers.

scholarly journals IDH mutation status is associated with distinct vascular gene expression signatures in lower-grade gliomas

2018 ◽  
Vol 20 (11) ◽  
pp. 1505-1516 ◽  
Author(s):  
Lei Zhang ◽  
Liqun He ◽  
Roberta Lugano ◽  
Kenney Roodakker ◽  
Michael Bergqvist ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Lower Grade ◽  
Idh Mutation ◽  
Wild Type ◽  
Who Grade ◽  
Mutation Status ◽  
Grade Ii ◽  
Grade Ii Glioma

Abstract Background Vascular gene expression patterns in lower-grade gliomas (LGGs; diffuse World Health Organization [WHO] grades II–III gliomas) have not been thoroughly investigated. The aim of this study was to molecularly characterize LGG vessels and determine if tumor isocitrate dehydrogenase (IDH) mutation status affects vascular phenotype. Methods Gene expression was analyzed using an in-house dataset derived from microdissected vessels and total tumor samples from human glioma in combination with expression data from 289 LGG samples available in the database of The Cancer Genome Atlas. Vascular protein expression was examined by immunohistochemistry in human brain tumor tissue microarrays (TMAs) representing WHO grades II–IV gliomas and nonmalignant brain samples. Regulation of gene expression was examined in primary endothelial cells in vitro. Results Gene expression analysis of WHO grade II glioma indicated an intermediate stage of vascular abnormality, less severe than that of glioblastoma vessels but distinct from normal vessels. Enhanced expression of laminin subunit alpha 4 (LAMA4) and angiopoietin 2 (ANGPT2) in WHO grade II glioma was confirmed by staining of human TMAs. IDH wild-type LGGs displayed a specific angiogenic gene expression signature, including upregulation of ANGPT2 and serpin family H (SERPINH1), connected to enhanced endothelial cell migration and matrix remodeling. Transcription factor analysis indicated increased transforming growth factor beta (TGFβ) and hypoxia signaling in IDH wild-type LGGs. A subset of genes specifically induced in IDH wild-type LGG vessels was upregulated by stimulation of endothelial cells with TGFβ2, vascular endothelial growth factor, or cobalt chloride in vitro. Conclusion IDH wild-type LGG vessels are molecularly distinct from the vasculature of IDH-mutated LGGs. TGFβ and hypoxia-related signaling pathways may be potential targets for anti-angiogenic therapy of IDH wild-type LGG.

scholarly journals P14.95 Is the pathological-grade relevant in “IDH-wild type, TERT-mutant” diffuse-gliomas? An analysis in 147 patients

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii90-iii90
Author(s):  
A E Danyeli ◽  
C B Akyerli ◽  
A Dinçer ◽  
E Coşgun ◽  
U Abacıoğlu ◽  
...  
Keyword(s):  
Overall Survival ◽  
Progression Free Survival ◽  
Genetic Alterations ◽  
Lower Grade ◽  
Wild Type ◽  
Ki 67 ◽  
Who Grade ◽  
Free Survival ◽  
Tert Promoter ◽  
Diffuse Gliomas

Abstract BACKGROUND Although the word “glioblastoma” still denotes a grade-IV pathology, basic molecular studies have clearly indicated that a significant proportion of lower-grade gliomas harbor genetic alterations typical of glioblastomas. Based on these findings cIMPACT-NOW update 3 has defined an entity called the “diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV”. A TERT-promoter mutation is one of these typical molecular markers of glioblastomas. In this study we analyzed IDH-wild type, TERT-mutant diffuse gliomas of different pathological grades to look for differences in demographic, clinical and survival characteristics. MATERIAL AND METHODS 147 adult hemispheric diffuse-gliomas with wild-type IDH1/2 and mutant TERT-promoter (C228T or C250T) were retrospectively analyzed. Primary thalamic, cerebellar brainstem or spinal cases were excluded. 126 (86%), 16(11%) and 5(3%) patients were WHO grade IV, III and II respectively. After surgical treatment or stereotactic biopsy all patients underwent chemoradiation. Median follow-up was 16mo (1–110). Tumors of different grades were compared for age, gender, multifocality, gliomatosis pattern, Ki-67 index, progression-free survival and overall-survival. RESULTS Mean age at presentation for grade II, III and IV were comparable (58.1, 58 and 58.1; ANOVA, p=0.72). There was a slight male predominance in both lower-grades and WHO-grade IV (M:F ratios 1.625 and 1.74). Mean Ki-67 index was significantly higher in higher grades (0.06, 0.14 and 0.25 for grades II, III and IV; ANOVA, p=0.001). Multifocality was comparable (chi-sq, p=1) in lower-grades (3/21; 14.3%) vs. WHO-grade IV (18/126; 14.3%). Gliomatosis pattern was comparable (chi-sq, p=0.095) in lower-grades (2/21; 9.5%) vs. (3/126; 2.3%). Median recurrence free survival (RFS) was 16 months (0–63) in lower-grades and 8months (1–50) in WHO-grade IV. PFS was significantly different between 3 WHO-grades (Log rank, p=0.007) and also between lower-grades and WHO-grade IV (Log rank, p=0.002). Median overall survival was 26 months(2–110) in lower-grades and 15mo(1–91) in WHO-grade IV. OS was significantly different between 3 WHO-grades (Log rank, p=0.014) and also between lower-grades and WHO-grade IV (Log rank, p=0.007). CONCLUSION Increasing pathological grades of hemispheric “IDH-wild type, TERT-mutant diffuse gliomas” have similar demographic and clinical characteristics but incrasing proliferation indices, decrasing progression free survival and shorter overall survival. The findings may be suggesitve of different grades of one common tumor entity.

scholarly journals IMT-01 THERAPEUTIC EFFECT AGAINST LOWER GRADE GLIOMA INDUCED BY DENDRITIC CELL BASED IMMUNOTHERAPY

2019 ◽  
Vol 1 (Supplement_2) ◽  
pp. ii17-ii17
Author(s):  
Yasuharu Akasaki ◽  
Jun Takei ◽  
Yuko Kamata ◽  
Yohei Yamamoto ◽  
Ryosuke Mori ◽  
...  
Keyword(s):  
Glioma Cells ◽  
Progression Free Survival ◽  
Cervical Region ◽  
Lower Grade ◽  
Mri Findings ◽  
Who Grade ◽  
Lower Grade Glioma ◽  
Major Interest ◽  
Grade Ii

Abstract BACKGROUND This trial was designed to evaluate the safety and clinical responses to an immunotherapy with fusions of dendritic and glioma cells in patients with lower grade glioma (LGG; WHO grade II-III glioma). METHOD Autologous cultured glioma cells obtained from surgical specimens were fused with autologous dendritic cells (DC) using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region of subjects. Toxicity, progression-free survival (PFS), overall survival (OS), and MRI findings were evaluated. DNA for whole exome and RNA for whole transcriptome extracted from HLA-A*24:02 positive glioma cells were analyzed by next generation sequencer. Variant peptides showing strong binding affinity to HLA-A*24:02 but not the corresponding wild type peptides were selected as candidate of neo-antigens. RESULTS The number of subjects of this trial were 24 (initially diagnosed cases: 20, recurrence cases: 4). WHO grade III cases were 20, and grade II cases were 4. Male were 15, and female were 9. Mean of follow up periods were 53.0 months (the longest follow up period: 1322 months). The number of events on PFS and OS were 8 and 6, respectively. Mean of candidate of neo-antigen peptides in HLA-A*24:02 positive patients (n=8) was 34. Among these candidates, twelve types of common neo-antigen peptide were identified. Neo-antigen peptides specifically expressed in the glioma cells from the effective group were not identified. CONCLUSIONS These results indicate that the efficacy of FC-immunotherapy may not always depend on the number of gene mutations or the expression of the specific neo-antigens. FC-immunotherapy, as a means of producing specific immunity against neo-antigens may safely induce anti-tumor effects in patients with LGG. Analysis of prognostic factor in glioma immunotherapy may be the next area of major interest.

scholarly journals OS10.1 Survival analysis of IDH wildtype astrocytomas with molecular features of glioblastoma, WHO grade IV

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii20-iii20 ◽  
Author(s):  
C M S Tesileanu ◽  
J A F Koekkoek ◽  
L Dirven ◽  
H J Dubbink ◽  
J M Kros ◽  
...  
Keyword(s):  
Molecular Data ◽  
Lower Grade ◽  
Who Grade ◽  
Historical Cohort ◽  
Molecular Features ◽  
Tert Promoter ◽  
Significant Difference ◽  
Tert Promoter Mutations ◽  
Grade Ii ◽  
Promoter Mutations

Abstract BACKGROUND Recently, isocitrate dehydrogenase wildtype (IDHwt) lower grade gliomas (LGGs) that have a telomerase reverse transcriptase (TERT) promoter mutation and/or gain of chromosome 7 combined with loss of chromosome 10 and/or epidermal growth factor receptor amplification have been reclassified as IDHwt astrocytomas with molecular features of glioblastoma, WHO grade IV (‘astrocytomas IDHwt, WHO IV’). Survival of these tumors meeting the criteria of these tumors is less well studied. The objective of this study is to compare the overall survival (OS) between the IDHwt astrocytomas, WHO IV and histological glioblastomas (GBMs). MATERIAL AND METHODS In this retrospective multicenter cohort study, all adult patients with a newly diagnosed IDHwt LGG (histologically WHO grade II or III) and with molecular data available were selected from the Erasmus MC and the LUMC from October 2002 to April 2019. LGG patients showing contrast enhancement with necrosis on the MRI at the time of histological diagnosis were excluded. Molecular data were determined using a diagnostic NGS panel. A historical cohort of 195 patients with IDHwt GBMs with molecular data available was used to compare OS. OS was measured from the date of the first diagnostic MR scan. RESULTS 79 IDHwt LGG patients were identified of which 62 patients had molecular features of glioblastoma (‘astrocytomas IDHwt, WHO IV’), 11 patients did not have these molecular features (‘astrocytomas IDHwt, WHO II & III’). In the remaining 6 patients the molecular data were not conclusive (astrocytomas IDHwt, WHO NOS). Patients with astrocytomas IDHwt, WHO IV were slightly older at diagnosis (median age = 57 years) than patients with GBMs IDHwt in the reference cohort or astrocytomas IDHwt, WHO II & III (respectively: median age 55 years, p=0.032 and 47 years, p=0.035). The relatively young age of our GBM IDHwt cohort reflects more extensive molecular testing in younger patients and histologically lower grade tumors. The median OS of astrocytomas IDHwt, WHO IV (23.8 months) was similar to the median OS of GBMs (19.2 months, log-rank test p=0.37). The median OS in 19 patients with only TERT promoter mutations was 16.8 months, similar to GBMs (p=0.94). CONCLUSION There is no statistically significant difference between the OS of IDHwt astrocytomas with molecular features of glioblastoma and the OS of true glioblastomas. Grade II and III IDHwt astrocytoma with molecular features of glioblastoma should be designated WHO grade IV. The presence of TERT promoter mutations alone in this histological context also qualifies for this designation.

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