Chemotherapy in low-grade gliomas

Clinical significance and molecular annotation of cellular morphometric subtypes in lower-grade gliomas discovered by machine learning

BACKGROUND

Lower-grade gliomas (LGG) are heterogeneous diseases by clinical, histological, and molecular criteria. We aimed to personalize the diagnosis and therapy of LGG patients by developing and validating robust cellular morphometric subtypes (CMS) and to uncover the molecular signatures underlying these subtypes.

METHODS

Cellular morphometric biomarkers (CMBs) were identified with artificial intelligence technique from TCGA-LGG cohort. Consensus clustering was used to define CMS. Survival analysis was performed to assess the clinical impact of CMBs and CMS. A nomogram was constructed to predict 3- and 5-year overall survival (OS) of LGG patients. Tumor mutational burden (TMB) and immune cell infiltration between subtypes were analyzed using the Mann-Whitney U test. The double-blinded validation for important immunotherapy-related biomarkers was executed using immunohistochemistry (IHC).

RESULTS

We developed a machine learning (ML) pipeline to extract CMBs from whole-slide images of tissue histology; identifying and externally validating robust CMS of LGGs in multicenter cohorts. The subtypes had independent predicted OS across all three independent cohorts. In the TCGA-LGG cohort, patients within the poor-prognosis subtype responded poorly to primary and follow-up therapies. LGGs within the poor-prognosis subtype were characterized by high mutational burden, high frequencies of copy number alterations, and high levels of tumor-infiltrating lymphocytes and immune checkpoint genes. Higher levels of PD-1/PD-L1/CTLA-4 were confirmed by IHC staining. In addition, the subtypes learned from LGG demonstrate translational impact on glioblastoma (GBM).

CONCLUSIONS

We developed and validated a framework (CMS-ML) for CMS discovery in LGG associated with specific molecular alterations, immune microenvironment, prognosis, and treatment response.

A cuproptosis-related lncRNAs signature for prognosis, chemotherapy, and immune checkpoint blockade therapy of low-grade glioma

Cuproptosis is a new type of cell death that is associated with mitochondrial respiration of the tricarboxylic acid cycle. Previous studies showed that long non-coding RNAs (lncRNAs) regulated low-grade glioma (LGG) progression. However, the potential applications of cuproptosis-related lncRNAs (CRLs) in LGG were not explored. A comprehensive analysis was performed in The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) cohorts. We first screened two distinct cuproptosis subtypes based on prognostic CRLs using consensus clustering. To facilitate individualized survival prediction in LGG, we constructed a prognostic signature (including CRNDE, HAR1A, and FAM181A-AS1) in the TCGA dataset. The prognostic signature exhibited excellent predictive ability and reliability, which was validated in the CGGA_325 and CGGA_693 datasets. Notably, patients in the high-risk group had increased immune cell infiltration and expression of immune checkpoints, which indicated that they may benefit more from immune checkpoint blockade (ICB) therapy. Finally, the prognostic signature screened the population with sensitivity to chemotherapy and ICB therapy. In summary, this study initially explored the mechanism of CRLs in LGG and provides some insights into chemotherapy and ICB therapy of LGG.

Colen R, Zinn PO. MRI-Based Radiomics and Radiogenomics in the Management of Low-Grade Gliomas: Evaluating the Evidence for a Paradigm Shift

Low-grade gliomas (LGGs) are tumors that affect mostly adults. These neoplasms are comprised mainly of oligodendrogliomas and diffuse astrocytomas. LGGs remain vexing to current management and therapeutic modalities although they exhibit more favorable survival rates compared with high-grade gliomas (HGGs). The specific genetic subtypes that these tumors exhibit result in variable clinical courses and the need to involve multidisciplinary teams of neurologists, epileptologists, neurooncologists and neurosurgeons. Currently, the diagnosis of an LGG pivots mainly around the preliminary radiological findings and the subsequent definitive surgical diagnosis (via surgical sampling). The introduction of radiomics as a high throughput quantitative imaging technique that allows for improved diagnostic, prognostic and predictive indices has created more interest for such techniques in cancer research and especially in neurooncology (MRI-based classification of LGGs, predicting Isocitrate dehydrogenase (IDH) and Telomerase reverse transcriptase (TERT) promoter mutations and predicting LGG associated seizures). Radiogenomics refers to the linkage of imaging findings with the tumor/tissue genomics. Numerous applications of radiomics and radiogenomics have been described in the clinical context and management of LGGs. In this review, we describe the recently published studies discussing the potential application of radiomics and radiogenomics in LGGs. We also highlight the potential pitfalls of the above-mentioned high throughput computerized techniques and, most excitingly, explore the use of machine learning artificial intelligence technologies as standalone and adjunct imaging tools en route to enhance a personalized MRI-based tumor diagnosis and management plan design.

CKMT1B is a potential prognostic biomarker and associated with immune infiltration in Lower-grade glioma

BACKGROUND

Lower-grade glioma (LGG) is the most common histology identified in glioma. CKMT1B has not been investigated in glioma. The purpose of this research was to investigate the prognostic value of CKMT1B and its correlation with immune infiltration in LGG.

METHODS

We used Gene Expression Profiling Interactive Analysis (GEPIA) to analyze the expression of CKMT1B in LGG. Univariate and multivariate Cox regression analyses were used to assess the effect of CKMT1B expression and screened variables on survival. The correlation between CKMT1B and immune infiltration was evaluated by TIMER and CIBERSORT. Moreover, the possible biological functions of CKMT1B were studied by GSEA. The statistical analysis was conducted by R software.

RESULTS

The expression of CKMT1B was significantly lower than the normal samples in LGG. Low expression of CKMT1B predicts a worse prognosis. Multivariate Cox analyses revealed that CKMT1B might be an independent favorable prognostic indicator. TIMER analysis revealed that CKMT1B expression level was related to immune infiltration. CIBERSORT analysis showed that CKMT1B expression was positively related to the infiltration level of activated mast cells and negatively related to macrophage M2 in LGG. Moreover, GESA showed that multiple cancer-related and immune-related gene sets were enriched in the low-CKMT1B group in the top 5 of the most significant differences.

CONCLUSION

CKMT1B is a prognostic biomarker with potential applications and associated with immune infiltration in Lower-grade glioma.

Short-term outcomes and predictors of post-surgical seizures in patients with supratentorial low-grade gliomas

To explore the predictive factors and short-term outcomes of post-surgical seizures in patients with supratentorial low-grade gliomas (LGGs). A consecutive series of 70 supratentorial LGG patients with seizures were reviewed to determine the predictors and short-term outcomes of seizures. Univariate analyses and multivariate logistic regression analyses were performed to determine the predictive factors associated with postoperative seizure outcomes. We identified the preoperative seizure frequency threshold by plotting a receiver operating characteristic curve. A Kaplan-Meier curve was constructed to illustrate the seizure-free survival rate of our cohort over time. 54 patients who remained seizure -free post-surgery were classified into the Engel class I, and the other 16 patients whose seizures relapsed were classified into Engel classes II-IV. Univariate and multivariate logistic regression analyses showed that the preoperative seizure frequency (X² = 16.069, P = 0.001), extent of resection (x² = 5.031, P = 0.025), IDH1 mutation (x² = 4.435, P = 0.035) and adjuvant chemotherapy of temozolomide (X² = 4.081, P = 0.043) were related to the postoperative short-term seizure outcome. The ROC curve indicated that the area under the curve for the preoperative seizure frequency test was 0.805 (95% confidence interval 0.690-0.920, p < 0.05), which corresponded to an optimal threshold of 2 preoperative seizures. The IDH1^WT status and adjuvant chemotherapy with temozolomide were related to a better post-operative seizure outcome. Within the first year after the surgical resection, seizures reoccurred among 16 patients (22.9%) with a mean time of 10.8 months. The preoperative seizure frequency, extent of resection, IDH1 status, and adjuvant chemotherapy with temozolomide were predictive factors of short-term postoperative seizure outcomes for supratentorial LGGs. To obtain a favorable seizure outcome, early intervention and removal are warranted. IDH1 mutation is the predictive biomarker of postoperative seizure outcomes. The adjuvant chemotherapy with temozolomide appears to be associated with better seizure outcomes, and it may be useful in helping to control the postoperative seizures.

Salinomycin exhibits anti-angiogenic activity against human glioma in vitro and in vivo by suppressing the VEGF-VEGFR2-AKT/FAK signaling axis

Tumor angiogenesis plays a crucial role in tumor growth, progression and metastasis, and suppression of tumor angiogenesis has been considered as a promising anticancer strategy. Salinomycin (SAL), an antibiotic, displays novel anticancer potential against several human cancer cells in vitro and in vivo. However, little information concerning its anti-angiogenic properties is available. Therefore, the anti‑angiogenic effect of SAL and the underlying mechanism in human glioma were evaluated in the present study. The results indicated that SAL treatment significantly inhibited human umbilical vein endothelial cell (HUVEC) proliferation, migration, invasion and capillary-like tube formation. Further investigation on intracellular mechanisms showed that SAL markedly suppressed FAK and AKT phosphorylation, and downregulated vascular endothelial growth factor (VEGF) expression in HUVECs. Pretreatment of cells with a PI3K inhibitor (LY294002) and FAK inhibitor (PF562271) markedly enhanced SAL-induced inhibition of HUVEC proliferation and migration, respectively. Moreover, U251 human glioma xenograft growth was also effectively blocked by SAL treatment in vivo via inhibition of angiogenesis involving FAK and AKT depho-sphorylation. Taken together, our findings validated that SAL inhibits angiogenesis and human glioma growth through suppression of the VEGF-VEGFR2-AKT/FAK signaling axis, indicating the potential application of SAL for the treatment of human glioma.

ARID4B is a good biomarker to predict tumour behaviour and decide WHO grades in gliomas and meningiomas

Aims

Although ARID4B is known to promote tumour metastasis in breast cancer and inhibit transformation and progression in leukaemia, the possible effect of ARID4B on primary brain tumours (PBTs) is not well characterised. We tested the hypothesis that expression of ARID4B correlates with WHO grade and survival in patients with PBTs.

Methods

Western blot analysis was performed on protein lysates prepared from normal brain tissue and glioma cell lines (U87MG, LN229, GBM8401 and U118MG). Subsequently, immunohistochemical analysis of ARID4B was performed on 2 tissue microarrays, including 12 normal brain tissues, 63 meningiomas with different subtypes, 232 gliomas of various grades and degrees of differentiation, 8 central neurocytomas and 4 chordomas. The ARID4B immunostaining score was calculated by multiplying the intensity score by the percentage of tumour cells expressing ARID4B.

Results

In vitro, ARID4B protein expression was increased in some glioma cell lines. In addition, the average ARID4B immunostaining score was 38.03, 79.09, 129.76 and 119.32, respectively, in gliomas of WHO grade I, II, III and IV. Higher ARID4B immunostaining score was significantly correlated with more advanced WHO grade of gliomas (p=7.4×10–6) and meningiomas. Finally, higher ARID4B expression tended to the shorter survival rates, but did not reach statistical significance.

Conclusions

ARID4B overexpression presented in most of PBTs, rather than non-neoplastic brain tissue, and correlated with WHO grades in meningiomas and gliomas. Therefore, ARID4B is a satisfactory biomarker to highlight tumour component and predict tumour behaviour in primary brain neoplasms.

Novel N-Substituted 2-(2-(Adamantan-1-yl)-1H-Indol-3-yl)-2-Oxoacetamide Derivatives: Synthesis and Biological Evaluation

In this study, a series of novel N-substituted 2-(2-(adamantan-1-yl)-1H-indol-3-yl)-2-oxoacetamide derivatives were synthesized, and evaluated for their cytotoxicity in human cell lines including Hela (cervical cancer), MCF7 (breast cancer ) and HepG2 (liver cancer). Several compounds were found to have potent anti-proliferative activity against those human cancer cell lines and compound 5r showed the most potent biological activity against HepG2 cells with an IC50 value of 10.56 ± 1.14 μΜ. In addition, bioassays showed that compound 5r induced time-dependent and dose-dependent cleavage of poly ADP-ribose polymerase (PARP), and also induced a dose-dependent increase in caspase-3 and caspase-8 activity, but had little effect on caspase-9 protease activity in HepG2 cells. These results provide evidence that 5r-induced apoptosis in HepG2 cell is caspase-8-dependent.

Increasing the Time Interval between PCV Chemotherapy Cycles as a Strategy to Improve Duration of Response in Low-Grade Gliomas: Results from a Model-Based Clinical Trial Simulation

Background. We previously developed a mathematical model capturing tumor size dynamics of adult low-grade gliomas (LGGs) before and after treatment either with PCV (Procarbazine, CCNU, and Vincristine) chemotherapy alone or with radiotherapy (RT) alone. Objective. The aim of the present study was to present how the model could be used as a simulation tool to suggest more effective therapeutic strategies in LGGs. Simulations were performed to identify schedule modifications that might improve PCV chemotherapy efficacy. Methods. Virtual populations of LGG patients were generated on the basis of previously evaluated parameter distributions. Monte Carlo simulations were performed to compare treatment efficacy across in silico clinical trials. Results. Simulations predicted that RT plus PCV would be more effective in terms of duration of response than RT alone. Additional simulations suggested that, in patients treated with PCV chemotherapy, increasing the interval between treatment cycles up to 6 months from the standard 6 weeks can increase treatment efficacy. The predicted median duration of response was 4.3 years in LGGs treated with PCV cycles given every 6 months versus 3.1 years in patients treated with the classical regimen. Conclusion. The present study suggests that, in LGGs, mathematical modeling could facilitate clinical research by helping to identify, in silico, potentially more effective therapeutic strategies.

Loss of Heterozygosity of 9p Is Associated with Poorer Survival in Patients with Gliomas

The prognostic factors associated with the survival of glioma patients have not been well established. Loss of heterozygosity (LOH) of 9p was known to be a typical molecular signature of gliomas, but it was still unclear whether LOH of 9p was associated with poorer survival in patients with gliomas. We searched PubMed and Embase databases from the earliest records to May 2015 to identify studies that met the inclusion criteria. Either a fixed- or a random-effects model was used to calculate the pooled hazard ratio (HR) according to the between-study heterogeneity. Thirteen eligible studies involving 1465 cases of gliomas were included in the meta-analysis. There was little between-study heterogeneity (I ² = 15 %), and the fixed-effects model was used to calculate the pooled HR. Meta-analysis of total 13 studies showed that LOH of 9p was significantly associated with poorer prognosis of glioma patients (HR = 1.39, 95%CI 1.17-1.64, P = 0.0002). Meta-analysis of eight studies reporting adjusted estimates showed that LOH of 9p was independently associated with poorer prognosis of glioma patients (HR = 1.40, 95%CI 1.14-1.72, P = 0.001). Subgroup analysis by types of gliomas showed that LOH of 9p was significantly associated with poorer prognosis in patients with glioblastoma (HR = 1.34, 95%CI 1.01-1.78, P = 0.04). There was no obvious risk of publication bias shown in the funnel plot. LOH of 9p is significantly associated with poorer prognosis of glioma patients, which is a useful biomarker in predicting patients' survival.

Seizure reduction is a prognostic marker in low-grade glioma patients treated with temozolomide

We aimed to analyze the value of seizure reduction and radiological response as prognostic markers of survival in patients with low-grade glioma (LGG) treated with temozolomide (TMZ) chemotherapy. We retrospectively reviewed adult patients with a progressive LGG and uncontrolled epilepsy in two hospitals (VUmc Amsterdam; MCH The Hague), who received chemotherapy with TMZ between 2002 and 2014. End points were a ≥50 % seizure reduction and MRI response 6, 12 and 18 months (mo) after the start of TMZ, and their relation with progression-free survival (PFS) and overall survival (OS). We identified 53 patients who met the inclusion criteria. Seizure reduction was an independent prognostic factor for both PFS (HR 0.38; 95 % CI 0.19–0.73; p = 0.004) and OS (HR 0.39; 95 % CI 0.18–0.85; p = 0.018) after 6mo, adjusting for age and histopathological diagnosis, as well as after 12 and 18mo. Patients with an objective radiological response showed a better OS (median 87.5mo; 95 % CI 62.0–112.9) than patients without a response (median 34.4mo; 95 % CI 26.1–42.6; p = 0.046) after 12mo. However, after 6 and 18mo OS was similar in patients with and without a response on MRI. Seizure reduction is an early and consistent prognostic marker for survival after treatment with TMZ, that seems to precede the radiological response. Therefore, seizure reduction may serve as a surrogate marker for tumor response.

Radiation therapy and grade II/III oligodendroglial tumors

Radiotherapy has been a longstanding treatment option for low-grade glioma. Improvements in tumor control and radiation-related toxicity may be attributed to advances in neuroimaging as well as radiotherapy planning and delivery. The discovery of various molecular prognostic factors have aided in patient selection for radiotherapy. These prognostic and predictive factors may also play a key role in determining which patients are likely to benefit most from combined systemic therapy and radiation.

Textural analysis of pre-therapeutic [18F]-FET-PET and its correlation with tumor grade and patient survival in high-grade gliomas

PURPOSE

Amino acid positron emission tomography (PET) with [18F]-fluoroethyl-L-tyrosine (FET) is well established in the diagnostic work-up of malignant brain tumors. Analysis of FET-PET data using tumor-to-background ratios (TBR) has been shown to be highly valuable for the detection of viable hypermetabolic brain tumor tissue; however, it has not proven equally useful for tumor grading. Recently, textural features in 18-fluorodeoxyglucose-PET have been proposed as a method to quantify the heterogeneity of glucose metabolism in a variety of tumor entities. Herein we evaluate whether textural FET-PET features are of utility for grading and prognostication in patients with high-grade gliomas.

METHODS

One hundred thirteen patients (70 men, 43 women) with histologically proven high-grade gliomas were included in this retrospective study. All patients received static FET-PET scans prior to first-line therapy. TBR (max and mean), volumetric parameters and textural parameters based on gray-level neighborhood difference matrices were derived from static FET-PET images. Receiver operating characteristic (ROC) and discriminant function analyses were used to assess the value for tumor grading. Kaplan-Meier curves and univariate and multivariate Cox regression were employed for analysis of progression-free and overall survival.

RESULTS

All FET-PET textural parameters showed the ability to differentiate between World Health Organization (WHO) grade III and IV tumors (p < 0.001; AUC 0.775). Further improvement in discriminatory power was possible through a combination of texture and metabolic tumor volume, classifying 85 % of tumors correctly (AUC 0.830). TBR and volumetric parameters alone were correlated with tumor grade, but showed lower AUC values (0.644 and 0.710, respectively). Furthermore, a correlation of FET-PET texture but not TBR was shown with patient PFS and OS, proving significant in multivariate analysis as well. Volumetric parameters were predictive for OS, but this correlation did not hold in multivariate analysis.

CONCLUSIONS

Determination of uptake heterogeneity in pre-therapeutic FET-PET using textural features proved valuable for the (sub-)grading of high-grade glioma as well as prediction of tumor progression and patient survival, and showed improved performance compared to standard parameters such as TBR and tumor volume. Our results underscore the importance of intratumoral heterogeneity in the biology of high-grade glial cell tumors and may contribute to individual therapy planning in the future, although they must be confirmed in prospective studies before incorporation into clinical routine.

Input of molecular analysis in medical management of primary brain tumor patients

Primary brain tumors comprise a large group of malignant and non-malignant tumors including heterogeneous entities with various biological and clinical behaviors. Up till recently, diagnosis of brain cancers, that drives treatment decision-making, was based on integration of clinical, radiological and pathological features of patients and tumors. Over the last years, practical neuro-oncology has entered an era of molecular-based personalized medicine. Indeed, molecular features of tumors provide critical information to physicians for daily clinical management of patients and for design of relevant clinical research. Sporadic gliomas or glial tumors are the most common primary brain tumors in adults. Recently, their medical management has been revolutionized by molecular data. Indeed, optimal therapeutic management of grade III glioma patients now requires assessment of chromosome arms 1p/19q copy number and IDH mutational statuses as predictive and prognostic biomarkers. Indeed, two large phase III clinical trials have demonstrated that early chemotherapy plus radiotherapy, versus radiotherapy alone, doubles median overall survival of patients suffering from 1p/19q co-deleted and/or IDH mutated anaplastic oligodendroglial tumor. Interestingly, both biomarkers have been identified in a large proportion of WHO grade II gliomas. Their clinical value, in this population, is under investigation through multiple phase III clinical trials. In sporadic WHO grade I gliomas, and specifically in pilocytic astrocytomas, MAPK signaling pathway activation is a frequent event, mainly due to genetic alterations involving BRAF gene. This characteristic opens new therapeutic perspectives using MAPK signaling pathway inhibitors. Finally, in the most aggressive gliomas, WHO grade IV gliomas, two critical biomarkers have been identified: (i) MGMT promoter methylation associated with longer survival and better response to chemotherapy and (ii) IDH mutations predicting better prognosis. Although, further studies are needed, MGMT promoter methylation will undoubtedly be transferred soon to clinical practice. Molecular characteristics are beginning to be valuable and indispensable in neuro-oncology for better management of brain tumors patients. The near future will be marked by identification of novel molecular biomarkers and their validation for clinical practice.

Seizure reduction in a low-grade glioma: more than a beneficial side effect of temozolomide

BACKGROUND

Seizures are a common symptom in patients with low-grade glioma (LGG), negatively influencing quality of life, if uncontrolled. Besides antiepileptic drugs, antitumour treatment might contribute to a reduction in seizure frequency. The aim of this study was to determine the effect of temozolomide (TMZ) chemotherapy on seizure frequency, to identify factors associated with post-treatment seizure reduction and to analyse the prognostic value of seizure reduction for survival.

METHODS

We retrospectively reviewed adult patients with supratentorial LGG and epilepsy who received chemotherapy with TMZ as initial treatment or for progressive disease in two hospitals (VUmc Amsterdam; MCH The Hague) between 2002 and 2012.

RESULTS

We identified 104 patients with LGG with epilepsy who had received TMZ. Uncontrolled epilepsy in the 3 months preceding chemotherapy was present in 66 of 104 (63.5%) patients. A ≥ 50% reduction in seizure frequency after 6 months occurred in 29 of 66 (43.9%) patients. Focal symptoms at presentation (OR 6.55; 95% CI 1.45 to 32.77; p = 0.015) appeared to be positively associated with seizure reduction. Seizure reduction was an independent prognostic factor for progression-free survival (HR 0.32; 95% CI 0.15 to 0.66; p = 0.002) and overall survival (HR 0.33; 95% CI 0.14 to 0.79; p = 0.013), along with a histological diagnosis of oligodendroglioma (HR 0.38; 95% CI 0.17 to 0.86; p = 0.021). Objective responses on MRI were similar for patients with and without seizure reduction.

CONCLUSIONS

TMZ may contribute to an important reduction in seizure frequency in patients with LGG. Seizure reduction following TMZ treatment has prognostic significance and may serve as an important clinical outcome measure in patients with LGG.

Seizure outcome after radiotherapy and chemotherapy in low-grade glioma patients: a systematic review

There is growing evidence that antitumor treatment contributes to better seizure control in low-grade glioma patients. We performed a systematic review of the current literature on seizure outcome after radiotherapy and chemotherapy and evaluated the association between seizure outcome and radiological response. Twenty-four studies were available, of which 10 described seizure outcome after radiotherapy and 14 after chemotherapy. All studies demonstrated improvements in seizure outcome after antitumor treatment. Eight studies reporting on imaging response in relation to seizure outcome showed a seizure reduction in a substantial part of patients with stable disease on MRI. Seizure reduction may therefore be the only noticeable effect of antitumor treatment. Our findings demonstrate the clinical relevance of monitoring seizure outcome after radiotherapy and chemotherapy, as well as the potential role of seizure reduction as a complementary marker of tumor response in low-grade glioma patients.

Prediction of glioma recurrence using dynamic ¹⁸F-fluoroethyltyrosine PET

BACKGROUND AND PURPOSE

Inter- and intratumor heterogeneity and the variable course of disease in patients with glioma motivate the investigation of new prognostic factors to optimize individual treatment. Here we explore the usefulness of standard static and more sophisticated dynamic (18)F-fluoroethyltyrosine-PET imaging for the assessment of patient prognosis.

MATERIALS AND METHODS

Thirty-four consecutive patients with untreated, first-diagnosed, histologically proved glioma were included in this retrospective study. All patients underwent dynamic PET scans before surgery (± standard treatment) and were followed up clinically and by MR imaging. Static and dynamic tumor-to-background ratio, TTP, and slope-to-peak were obtained and correlated with progression-free survival.

RESULTS

Twenty of 34 patients experienced progression, with a median progression-free survival of 28.0 ± 11.1 months. Dynamic TTP was highly prognostic for recurrent disease, showing a strong correlation with progression-free survival (hazard ratio, 6.050; 95% CI, 2.11-17.37; P < .001). Most interesting, this correlation also proved significant in the subgroup of low-grade glioma (hazard ratio, 5.347; 95% CI, 1.05-27.20; P = .044), but not when using established static imaging parameters, such as maximum tumor-to-background ratio and mean tumor-to-background ratio. In the high-grade glioma subgroup, both dynamic and static parameters correlated with progression-free survival. The best results were achieved by defining ROIs around "hot spots" in earlier timeframes, underlining the concept of intratumor heterogeneity.

CONCLUSIONS

(18)F-fluoroethyltyrosine-PET can predict recurrence in patients with glioma, with dynamic analysis showing advantages over static imaging, especially in the low-grade subgroup.

Supratentorial low-grade diffuse astrocytoma: medical management

Diffuse astrocytomas (DAs) represent less than 10% of all gliomas. They are diffusely infiltrating World Health Organization (WHO) grade II neoplasms that have a median survival in the range of 5-7 years, generally with a terminal phase in which they undergo malignant transformation to glioblastoma (GBM). The goals of treatment in addition to prolonging survival are therefore to prevent progression and malignant transformation, as well as optimally managing symptoms, primarily tumor-associated epilepsy. Available data suggest that the course of this disease is only minimally impacted by adjuvant therapies and that there does not seem to be much difference in terms of outcome of whether patients are treated in the adjuvant setting with irradiation or chemotherapy. We review the experience with chemotherapy as a treatment modality and offer some guidelines for its usage and discuss medical management of arising symptoms.

Predictive biomarkers in adult gliomas: the present and the future

PURPOSE OF REVIEW

This review summarizes recent studies on the predictive value of molecular markers in adult gliomas, including 1p/19q codeletion, MGMT methylation, IDH mutation and markers identified using omics and next-generation sequencing studies.

RECENT FINDINGS

The long-term results of the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer trials in anaplastic oligodendroglial glioma have shown that the 1p/19q codeletion predicts an overall survival benefit from early PCV (procarbazine CCNU vincristine) chemotherapy. This benefit can also be predicted using gene expression-based molecular subtypes of gliomas while the predictive value of the IDH mutation in this context requires further study. In elderly patients with glioblastoma, the analysis of MGMT methylation status in two phase III trials suggests that this alteration may guide treatment decisions; however, this finding still needs confirmation in prospective studies. Omics and next-generation sequencing studies have identified additional potential predictive markers. In particular, IDH mutations, BRAF V600E mutations and FGFR gene fusions might predict efficacy of therapies targeted against these alterations.

SUMMARY

Currently, the 1p/19q codeletion is the only well established predictive marker with clinical utility. However, it is likely that other molecular markers such as MGMT methylation, IDH mutation and those identified using omics and next-generation sequencing studies will further guide treatment decisions in adult gliomas.

Where are we now? And where are we going? A report from the Accelerate Brain Cancer Cure (ABC2) low-grade glioma research workshop

Diffuse gliomas consist of both low- and high-grade varieties, each with distinct morphological and biological features. The often extended periods of relative indolence exhibited by low-grade gliomas (LGG; WHO grade II) differ sharply from the aggressive, rapidly fatal clinical course of primary glioblastoma (GBM; WHO grade IV). Nevertheless, until recently, the molecular foundations underlying this stark biological contrast between glioma variants remained largely unknown. The discoveries of distinctive and highly recurrent genomic and epigenomic abnormalities in LGG have both informed a more accurate classification scheme and pointed to viable avenues for therapeutic development. As such, the field of neuro-oncology now seems poised to capitalize on these gains to achieve significant benefit for LGG patients. This report will briefly recount the proceedings of a workshop held in January 2013 and hosted by Accelerate Brain Cancer Cure (ABC(2)) on the subject of LGG. While much of the meeting covered recent insights into LGG biology, its focus remained on how best to advance the clinical management, whether by improved preclinical modeling, more effective targeted therapeutics and clinical trial design, or innovative imaging technology.