Chemoradiation for anaplastic oligodendrogliomas: clinical outcomes and prognostic value of molecular markers

BTN2A2, a new biomarker and therapeutic target for glioma

BACKGROUND

Protein casein 2A2 (BTN2A2) is a costimulatory molecule first identified in antigen-presenting cells. Studies have shown the involvement of BTN2A2 in immunity. However, the exact role and the mechanism of BTN2A2 in tumors are still unclear.

METHODS

First, we performed real-time PCR to measure BTN2A2 expression in glioma cell lines. Next, we performed Genes Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to understand the mechanism of BTN2A2 in glioma. Next, we used the "ESTIMATE", "ssGSEA" and "CIBERSORT" algorithms to analyze the correlation between BTN2A2 and immune cell infiltration (ICI). Finally, we performed immunohistochemistry, growth curve, transwell, and colony formation assays to determine the functions of BTN2A2 in glioma.

RESULTS

Our results showed an increase in BTN2A2 expression levels in glioma tissues and cells. Next, we determined that BTN2A2 was correlated with the prognosis of patients with glioma. Then, using the ESTIMATE, ssGSEA, and CIBERSORT algorithms, we discovered that BTN2A2 was significantly associated with immune cell infiltration (ICI) in glioma. We observed an increase in BTN2A2 expression levels with an increase in the patient's tumor grade. Furthermore, BTN2A2 significantly enhanced the proliferative and migratory abilities of glioma cells.

CONCLUSIONS

Our results showed a significant increase in BTN2A2 expression levels in glioma cells and tissues. Furthermore, the prognosis of patients expressing high BTN2A2 levels was poor. Moreover, BTN2A2 was correlated with progression and ICI in patients with glioma. Together, this indicates that BTN2A2 could be a therapeutic target for patients with glioma.

The Evaluation of Radiomic Models in Distinguishing Pilocytic Astrocytoma From Cystic Oligodendroglioma With Multiparametric MRI

PURPOSE

To assess whether a machine-learning model based on texture features extracted from multiparametric magnetic resonance imaging could yield an accurate diagnosis in differentiating pilocytic astrocytoma from cystic oligodendrogliomas.

MATERIALS AND METHODS

The preoperative images from multisequences were used for tumor segmentation. Radiomic features were extracted and selected for machine-learning models. Semantic features and selected radiomic features from training data set were built, and the performance of each model was evaluated by receiver operating characteristic curve and accuracy from isolated testing data set.

RESULTS

In terms of different sequences, the best classifier was built by radiomic features extracted from enhanced T1WI-based classifier. The best model in our study turned out to be the gradient boosted trees classifier with an area under curve value of 0.99.

CONCLUSION

Our study showed that gradient boosted trees based on texture features extracted from enhanced T1WI could become an additional tool for improving diagnostic accuracy to differentiate pilocytic astrocytoma from cystic oligodendroglioma.

Comprehensive analysis of genes based on chr1p/19q co-deletion reveals a robust 4-gene prognostic signature for lower grade glioma

Purpose: The chr1p/19q co-deletion is a favorable prognostic factor in patients with lower grade glioma. The aim of this study was to reveal key genes for prognosis and establish prognostic gene signatures based on genes encoded by chr1p/19q. Materials and methods: The data was downloaded from The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA) and Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) between lower grade glioma tissue and normal brain were identified. The univariate COX regression, robust likelihood-base survival analysis (rbsurv) and multivariate COX regression analysis were used to establish the 4-gene-signature based on the DEGs. The receiver operating characteristic (ROC) curve and the Kaplan-Mere curve were used to verify the prediction accuracy of the signature. Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were also performed to explore the reasons for good prognosis in patients with chr1p/19q deletion. Results: A total of 1346 DEGs were identified between lower grade glioma samples and normal brain samples in GSE16011, including 56 up-regulated mRNAs located on chr1p and 20 up-regulated mRNAs located on chr19q. We established a 4-gene-signature that was significantly associated with survival based on the 76 gene. The AUC of the 4-gene-signature for 5-year OS in TCGA and CGGA was 0.837 and 0.876, respectively, which was superior compared to other parameters such as chr1p/19q co-deletion, IDH mutant, WHO grade and histology type, especially in chr1p/19q non-co-deletion patients. GSEA and KEGG analysis suggested that the prolongation of chr1p/19q in patients could be associated with cell cycle and DNA mismatch repairing. Conclusions: We established a robust 4-gene-signature based on the chr1p/19q and we explored the potential function of these newly identified survival-associated genes by bioinformatics analysis. The 4-gene from the signature are promising molecular targets to be used in the future.

18F-DOPA uptake does not correlate with IDH mutation status and 1p/19q co-deletion in glioma

OBJECTIVE

The role of amino acid positron emission tomography (PET) in glioma grading and outcome prognostication has not yet been well established. This is particularly true in the context of the new WHO 2016 classification, which introduced a definition of glioma subtypes primarily based on molecular fingerprints. The aim of the present study was to correlate 3,4‑dihydroxy‑6‑[¹⁸F]‑fluoro-L‑phenylalanine (F-DOPA) uptake parameters with IDH mutation, 1p/19q status, and survival outcomes in patients with glioma.

METHODS

The study population consisted of 33 patients (17 M/16 F, mean age: 46 ± 13 years) who underwent F-DOPA PET/CT for the evaluation of tumor extent before the start of chemo or radiotherapy. The presence of IDH mutation and 1p/19q status was assessed in all the cases. Tumor volume and semiquantitative uptake parameters, namely SUV_max, tumor-to-normal brain ratio and tumor-to-normal striatum ratio, were calculated for each tumor. Imaging-derived parameters were compared between patients stratified according to molecular fingerprints, using parametric or non-parametric tests, where appropriate. The Kaplan-Meier method was used to assess differences of overall survival (OS) and progression-free survival (PFS) between groups. PET parameters were also tested as prognostic factors in univariate Cox survival regression models.

RESULTS

There were 12 IDH-wild-type and 21 IDH-mutant patients. Stratification according to 1p/19q co-deletion resulted in 20 non-co-deleted and 13 co-deleted patients. Median follow-up time from PET/CT exam was 30.5 months (range 3.5-74 months). Semiquantitative uptake parameters did correlate neither with IDH mutation nor with 1p/19q status. Uptake was similar in low-grade and high-grade tumors, respectively. In addition, F-DOPA uptake parameters, macroscopic tumor volume, or tumor grade did not stratify OS, while a correlation between SUV_max and PFS was shown in the subgroup of astrocytomas. On the other hand, IDH mutation status and presence of 1p/19q co-deletion had a significant impact on survival outcomes. The prognostic value of IDH mutation status was also confirmed in the subgroup of patients with astrocytic tumors.

CONCLUSIONS

F-DOPA uptake parameters do not correlate with tumor molecular and histological characteristics. The predictive value of PET-derived parameters on outcomes of survival is limited.

Utilization and impact of adjuvant therapy in anaplastic oligodendroglioma: an analysis on 1692 patients

The aim of this study was to determine the utilization rates and impact of adjuvant therapy on overall survival (OS) for anaplastic oligodendroglioma (AO). Data were extracted from the National Cancer Data Base (NCDB). Chi square test, Kaplan-Meier method, and Cox regression models were employed in SPSS 22.0 (Armonk, NY: IBM Corp.) for data analyses. 1692 patients with AO who underwent surgery were identified. 945 (55.9 %) received adjuvant radiotherapy with concomitant chemotherapy (chemoRT), 102 (6.0 %) adjuvant radiotherapy (RT) sequentially followed by chemotherapy, 244 (14.4 %) adjuvant RT alone, and 401 (23.7 %) received no adjuvant therapy. Patients were more likely to receive adjuvant chemoRT if they were diagnosed in 2009-2013 vs. 2004-2008 (p < 0.001), had Karnofsky Performance Status >70 vs. <70 (p = 0.018), had private insurance vs. Medicaid vs. no insurance (p < 0.001), or had median income ≥$63,000 vs. <$63,000 (p = 0.014). Those who received adjuvant chemoRT (concomitant or sequential) had significantly better 5-year OS than those who received adjuvant RT alone or no adjuvant therapy (59.8 % vs. 65.0 % vs. 44.9 % vs. 45.6 %, p < 0.001). This significant 5-year OS benefit was also observed regardless of age. There was no difference in OS when comparing concomitant chemoRT to sequential RT and chemotherapy (p = 0.481). On multivariate analysis, receipt of adjuvant chemoRT (concomitant or sequential) remained an independent prognostic factor for improved OS. Adjuvant chemoRT (concomitant or sequential) is an independent prognostic factor for improved OS in anaplastic oligodendroglioma and should be considered for all clinically suitable patients who have undergone surgery for the disease.

A multicenter study of anaplastic oligodendroglioma: the Korean Radiation Oncology Group Study 13-12

Although some existing evidence supports the addition of chemotherapy (CT) to radiation therapy (RT) for anaplastic oligodendroglioma treatment, controversy about both the criteria for suitable candidates and the optimal treatment schedule remains. We reviewed data from 376 newly diagnosed anaplastic oliogodendroglial tumor patients from nine Korean institutes were reviewed from 2000 to 2010. Total tumor removal was performed in 146 patients. More than 85% of the entire patients received postoperative RT, and 59% received CT. Approximately 50% (n = 189) received CT in addition to RT and 9% (n = 32) received CT only. A multivariate analysis revealed that younger age, frontal lobe location of the tumor, gross total removal, 1p/19q codeletion, and initial RT were associated with longer progression-free and overall survival rates. No difference was observed in outcomes from the treatment that included either temozolomide or PCV (procarbazine, lomustine, and vincristine) in addition to RT regardless of the 1p/19q deletion status. A clear improvement in progression-free and overall survival was observed for RT and combined CT/RT in compared with CT only. Postoperative RT appears to improve survival for entire group thus total removal and 1p/19q codeletion may not be sufficient criteria to omit RT as a treatment option. These results suggest that RT should continue to be offered as the standard treatment option for patients with anaplastic oligodendroglial tumors.

Anaplastic glioma: current treatment and management

Anaplastic glioma (AG) is divided into three morphology-based groups (anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic oligoastrocytoma) as well as three molecular groups (glioma-CpG island methylation phenotype [G-CIMP] negative, G-CIMP positive non-1p19q codeleted tumors and G-CIMP positive codeleted tumors). The RTOG 9402 and EORTC 26951 trials established radiotherapy plus (procarbazine, lomustine, vincristine) chemotherapy as the standard of care in 1p/19q codeleted AG. Uni- or non-codeleted AG are currently best treated with radiotherapy only or alkylator-based chemotherapy only as determined by the NOA-04 trial. Maturation of NOA-04 and results of the currently accruing studies, CODEL (for codeleted AG) and CATNON (for uni or non-codeleted AG), will likely refine current up-front treatment recommendations for AG.

The future of high-grade glioma: Where we are and where are we going

High-grade glioma (HGG) are optimally treated with maximum safe surgery, followed by radiotherapy (RT) and/or systemic chemotherapy (CT). Recently, the treatment of newly diagnosed anaplastic glioma (AG) has changed, particularly in patients with 1p19q codeleted tumors. Results of trials currenlty ongoing are likely to determine the best standard of care for patients with noncodeleted AG tumors. Trials in AG illustrate the importance of molecular characterization, which are germane to both prognosis and treatment. In contrast, efforts to improve the current standard of care of newly diagnosed glioblastoma (GB) with, for example, the addition of bevacizumab (BEV), have been largely disappointing and furthermore molecular characterization has not changed therapy except in elderly patients. Novel approaches, such as vaccine-based immunotherapy, for newly diagnosed GB are currently being pursued in multiple clinical trials. Recurrent disease, an event inevitable in nearly all patients with HGG, continues to be a challenge. Both recurrent GB and AG are managed in similar manner and when feasible re-resection is often suggested notwithstanding limited data to suggest benefit from repeat surgery. Occassional patients may be candidates for re-irradiation but again there is a paucity of data to commend this therapy and only a minority of selected patients are eligible for this approach. Consequently systemic therapy continues to be the most often utilized treatment in recurrent HGG. Choice of therapy, however, varies and revolves around re-challenge with temozolomide (TMZ), use of a nitrosourea (most often lomustine; CCNU) or BEV, the most frequently used angiogenic inhibitor. Nevertheless, no clear standard recommendation regarding the prefered agent or combination of agents is avaliable. Prognosis after progression of a HGG remains poor, with an unmet need to improve therapy.

Incorporation of biomarkers in phase II studies of recurrent glioblastoma

The survival trends for glioblastoma (GBM) patients have remained largely static, reflecting a lack of improvement in the therapeutic options for patients. Less than 5 % of newly diagnosed GBM survives more than 5 years. Tumor relapse is nearly universal and the majority of patients do not respond to further systemic therapy. The results from phase II studies conducted with recurrent GBM patients have not translated to successful confirmatory studies and thus we have reached a significant roadblock in the development of new treatments for patients with recurrent GBM. The development of new, active, and potentially targeted drugs for the treatment of recurrent GBM represents a major unmet need. The incorporation of diagnostic/companion biomarker combinations into the phase II studies and appropriate stratification of the patients is lagging significantly behind other larger cancer groups such as breast, non-small cell lung cancer, and melanoma. We herein carried out a systematic review of the phase II clinical studies conducted in patients with recurrent GBM (2010-2013 inclusive) to assess the degree of biomarker incorporation within the clinical trial design.

Oligodendroglial tumors

Oligodendroglial tumors are relatively rare, comprising approximately 5% of all glial neoplasms. Oligodendroglial tumor patients have a better prognosis than those with astrocytic neoplasms, and patients with tumors that contain 1p/19q co-deletions or IDH-1 mutations appear to be particularly sensitive to treatment. In the past decade, scientists have made significant progress in the unraveling the molecular events that relate to the pathogenesis of these neoplasms. There is considerable excitement resulting from the recent reports from two large phase III randomized trials (European Organization for Research and Treatment of Cancer [EORTC] 26951 and Radiation Therapy Oncology Group [RTOG] 9402), which disclosed that patients with newly diagnosed 1p/19q co-deleted anaplastic oligodendroglial tumors have a 7+year increase in median overall survival following chemoradiation, as compared to radiation alone. This has stimulated a renewed interest in the development of new therapeutic strategies for treatment and potential cure of oligodendroglial tumors, based on an improved scientific understanding of the molecular events involved in the pathogenesis of these neoplasms. The goal of this document is to summarize the key translational developments and recent clinical therapeutic trial data, with a correlative perspective on current and future directions.

IDH1 mutation and MGMT methylation status predict survival in patients with anaplastic astrocytoma treated with temozolomide-based chemoradiotherapy

Several molecular markers have been proposed as predictors of outcome in patients with high grade gliomas. We report a retrospective multicenter study of 97 consecutive adult patients with anaplastic astrocytoma (AA) treated with radiation therapy (RT) plus concomitant and adjuvant temozolomide (TMZ) between October 2004 and March 2012. Correlations between the isocitrate dehydrogenase 1 (IDH1) mutation and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation with survival outcomes have been analyzed. At a median follow-up time of 46 months (range 12-89 months), median and 5-year overall survival rates were 50.5 months (95 % CI, 37.8-63.2) and 38% (95 % CI, 25.7-50.7%), and median and 5-year progression-free survival rates were 36 months (95% CI, 28.5-44.0) and 22 % (95 % CI, 10-34%), respectively. IDH1 mutation and MGMT promoter methylation were present in 54 and 60% of evaluable patients, respectively. Multivariate Cox proportional hazards regression analysis showed that IDH1 mutation (P = 0.001), MGMT methylation (P = 0.01), age < 50 years (P = 0.02), and extent of resection (P = 0.04) were significantly associated with longer survival. Our study confirms the favorable prognostic value of IDH1 mutation and MGMT methylation in patients with AA treated with RT plus concomitant and adjuvant TMZ. The superiority of combined radiochemotherapy over other treatment modalities remains to be demonstrated.