WHO Grade II-III Gliomas Research Articles

343MO Clinical features and DNA methylation patterns in long- and short-term survivors of WHO grade II-III glioma

WHO grade II-III gliomas affect rather young individuals and are characterized by a heterogenous survival prognosis ranging from months to years. Postoperative treatment prolongs survival but potentially impacts long-term quality of life and cognitive functioning. Therefore, refined prognostic stratification models are needed to guide future treatment studies.

LAG-3 expression in the inflammatory microenvironment of glioma

PurposeImmune modulatory therapies including immune checkpoint inhibitors have so far failed to result in clinically meaningful efficacy in glioma. We aimed to investigate lymphocyte activation gene 3 (LAG-3), an inhibitory receptor on immune cells and target of second-generation immune checkpoint inhibitors, in glioma.Methods97 patients with diffuse glioma (68 with glioblastoma, 29 with WHO grade II-III glioma) were identified from the Neuro-Biobank of the Medical University of Vienna. LAG-3 expression in the inflammatory microenvironment was assessed by immunohistochemistry (monoclonal anti-LAG-3 antibody, clone 17B4) and correlated to CD3+ , CD8+ , CD20+ and PD-1+ tumor-infiltrating lymphocytes (TILs) and PD-L1 expression on tumor cells.ResultsLAG-3+ TILs could be observed in 10/97 (10.3%) IDH-wildtype samples and in none of the included IDH-mutant glioma samples (p = 0.057). Further, LAG-3+ TILs were only observed in WHO grade IV glioblastoma, while none of the investigated WHO grade II–III glioma presented with LAG-3+ TILs (p = 0.03). No association of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation and presence of LAG-3+ TILs was observed (p = 0.726). LAG-3 expression was associated with the presence of CD3+ (p = 0.029), CD8+ (p = 0.001), PD-1+ (p < 0.001) TILs and PD-L1+ tumor cells (p = 0.021), respectively. No association of overall survival with LAG-3+ TIL infiltration was evident (median OS 9.9 vs. 14.2 months, p = 0.95).ConclusionsLAG-3 is only rarely expressed on TILs in IDH-wildtype glioma and associated with active inflammatory milieu as defined by higher TIL density. Immune microenvironment diversity should be considered in the design of future immunotherapy trials in glioma.

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

BACKGROUNDThis 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).METHODAutologous 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.RESULTSThe 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.CONCLUSIONSThese 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.

Inter-rater agreement in glioma segmentations on longitudinal MRI.

BackgroundTumor segmentation of glioma on MRI is a technique to monitor, quantify and report disease progression. Manual MRI segmentation is the gold standard but very labor intensive. At present the quality of this gold standard is not known for different stages of the disease, and prior work has mainly focused on treatment-naive glioblastoma. In this paper we studied the inter-rater agreement of manual MRI segmentation of glioblastoma and WHO grade II-III glioma for novices and experts at three stages of disease. We also studied the impact of inter-observer variation on extent of resection and growth rate.MethodsIn 20 patients with WHO grade IV glioblastoma and 20 patients with WHO grade II-III glioma (defined as non-glioblastoma) both the enhancing and non-enhancing tumor elements were segmented on MRI, using specialized software, by four novices and four experts before surgery, after surgery and at time of tumor progression. We used the generalized conformity index (GCI) and the intra-class correlation coefficient (ICC) of tumor volume as main outcome measures for inter-rater agreement.ResultsFor glioblastoma, segmentations by experts and novices were comparable. The inter-rater agreement of enhancing tumor elements was excellent before surgery (GCI 0.79, ICC 0.99) poor after surgery (GCI 0.32, ICC 0.92), and good at progression (GCI 0.65, ICC 0.91). For non-glioblastoma, the inter-rater agreement was generally higher between experts than between novices. The inter-rater agreement was excellent between experts before surgery (GCI 0.77, ICC 0.92), was reasonable after surgery (GCI 0.48, ICC 0.84), and good at progression (GCI 0.60, ICC 0.80). The inter-rater agreement was good between novices before surgery (GCI 0.66, ICC 0.73), was poor after surgery (GCI 0.33, ICC 0.55), and poor at progression (GCI 0.36, ICC 0.73). Further analysis showed that the lower inter-rater agreement of segmentation on postoperative MRI could only partly be explained by the smaller volumes and fragmentation of residual tumor. The median interquartile range of extent of resection between raters was 8.3% and of growth rate was 0.22 mm/year.ConclusionManual tumor segmentations on MRI have reasonable agreement for use in spatial and volumetric analysis. Agreement in spatial overlap is of concern with segmentation after surgery for glioblastoma and with segmentation of non-glioblastoma by non-experts.

Impact of concurrent versus adjuvant chemotherapy on the severity and duration of lymphopenia in glioma patients treated with radiation therapy.

Prolonged severe lymphopenia has been shown to persist beyond a year in glioma patients after radiation therapy (RT) with concurrent and adjuvant chemotherapy. This study examines the differential impact of concurrent versus adjuvant chemotherapy on lymphopenia after RT. WHO grade II-III glioma patients who received RT with concurrent and/or adjuvant chemotherapy from 2007 to 2016 were retrospectively analyzed. Concurrent chemotherapy was temozolomide (TMZ), and adjuvant chemotherapy was either TMZ or procarbazine/lomustine/vincristine (PCV). Absolute lymphocyte count (ALC) was analyzed at baseline, 1.5, 3, 6, and 12 months after the start of RT. Univariable and multivariable logistic regression were used to identify the clinical variables in predicting acute or late lymphopenia. There were151 patients with evaluable ALC: 91 received concurrent and adjuvant TMZ (CRT + ADJ), 32 received only concurrent TMZ (CRT), and 28 received only adjuvant TMZ or PCV (ADJ). There were 9 (10%) versus 6 (19%) versus 0 (0%) cases of grade 3 lymphopenia (ALC < 500/mm3) at 6 weeks and 4 (6%) versus 0 (0%) versus 3 (17%) cases at 12 months in CRT + ADJ, CRT and ADJ groups, respectively. On multivariable analyses, concurrent chemotherapy (odds ratio [OR] 72.3, p < 0.001), female sex (OR 10.8, p < 0.001), and older age (OR 1.06, p = 0.002) were the most significant predictors for any grade ≥ 1 lymphopenia (ALC < 1000/mm3) at 1.5 months. Older age (OR 1.08, p = 0.02) and duration of adjuvant chemotherapy (OR 1.19, p = 0.003) were significantly associated with grade ≥ 1 lymphopenia at 12 months. Thus,concurrent chemotherapy appears as the dominant contributor to the severity of acute lymphopenia after RT in WHO grade II-III glioma patients, and duration of adjuvant chemotherapy appears as the key factor to prolonged lymphopenia.

The etiopathogenesis of diffuse low-grade gliomas

The origins of diffuse low-grade gliomas (DLGG) are unknown. Beyond some limited data on their temporal and cellular origins, the mechanisms and risk factors involved are poorly known. First, based on strong relationships between DLGG development and the eloquence of brain regions frequently invaded by these tumors, we propose a "functional theory" to explain the origin of DLGG. Second, the biological pathways involved in DLGG genesis may differ according to tumor location (anatomo-molecular correlations). The cellular and molecular mechanisms of such "molecular theory" will be reviewed. Third, the geographical distribution of diffuse WHO grade II-III gliomas within populations is heterogeneous, suggesting possible environmental risk factors. We will discuss this "environmental theory". Finally, we will summarize the current knowledge on genetic susceptibility in gliomas ("genetic predisposition theory"). These crucial issues illustrate the close relationships between the pathophysiology of gliomagenesis, the anatomo-functional organization of the brain, and personalized management of DLGG patients.

In vitro visualization and characterization of wild type and mutant IDH homo- and heterodimers using Bimolecular Fluorescence Complementation.

Mutations in the metabolic enzyme isocitrate dehydrogenase (IDH) were recently found in ~80% of WHO grade II–III gliomas and secondary glioblastomas. These mutations reduce the enzyme’s ability to convert isocitrate to α-ketoglutarate and, instead, confer a novel gain-of-function resulting in the conversion of α-ketoglutarate to 2-hydroxglutarate (2-HG). However, IDH mutations exist in a heterozygous state such that a functional wild type allele is retained. Recent data suggest that the ability of mutant IDH1, but not mutant IDH2, to produce 2-HG is dependent on the activity of the retained wild type allele. In this study, we aimed to further our understanding of the interaction and function of wild type and mutant IDH heterodimers utilizing Bimolecular Fluorescence Complementation (BiFC). Dimerization of wild type and mutant IDH monomers conjugated to the N- and C-terminus of Venus protein, respectively, is directly proportional to the amount of fluorescence emitted and can be used as an approach to visualize and assess IDH dimerization. Thus, we utilized this method to visualize IDH homo- and heterodimers and to examine their cellular physiology based on subcellular localization, NADPH production, and 2-HG levels. Our results demonstrate that wild type and mutant IDH1 or IDH2 heterodimers display similar physiological characteristics to that of mutant IDH1 or IDH2 homodimers with the exception of their ability to generate NADPH. IDH1 heterodimers consistently generate NADPH whereas IDH2 heterodimers do not. However, the presence of mutant IDH1 or IDH2 in homo- or heterodimer configurations consistently generates equivalent levels of 2-HG. Our data suggest that the wild type protein is not required for the generation of 2-HG.

Subgrouping of gliomas on the basis of genetic profiles

Management of gliomas depends on histological diagnosis; there are, however, limitations to the systems presently used. Tumors in the same entity can have different clinical courses, especially when they are diagnosed as WHO grade II-III. Previous studies revealed that genetic subgrouping of gliomas provides useful information that could help establishment of treatment procedures on the basis of the genetic background of the tumors. Recently, the authors analyzed the chromosomal copy number aberrations (CNAs) of adult supratentorial gliomas by comparative genomic hybridization using microdissected tissue sections. The tumors were classified into subgroups according to chromosomal CNAs. WHO grade II-III gliomas contained a variety of genetic subgroups that correlated well with the clinical course. Of these, long progression-free survival was observed for tumors with +7q and those with -1p/19q, low-grade tumors of 2 major lineages, and, in our preliminary data, both were closely correlated with mutation of IDH1. Furthermore, in contrast with +7q tumors, the great majority of +7 or +7/-10q groups had wildtype IDH1. Genetic studies suggest that cytogenetic characterization may provide an additional classification system for gliomas, and new criteria could help to establish rational and objective means for analysis of treatment procedures.