Prognostic markers in gliomas

Alpha Internexin: A Surrogate Marker for 1p/19q Codeletion and Prognostic Marker in Anaplastic (WHO grade III) Gliomas

Background

The WHO 2016 classification of diffuse gliomas has incorporated molecular markers isocitrate dehydrogenase (IDH) gene mutations (IDHmut) and codeletion of chromosomal arms 1p and 19q (1p/19q codeletion) as tumor defining entities. The diagnosis of diffuse oligodendrogliomas (ODG) and anaplastic oligodendroglioma (AO) mandatorily requires the demonstration of IDH1 and/or IDH2 mutations along with 1p/19q codeletion, whereas the 1p/19q noncodeleted diffuse gliomas are labeled as astrocytomas. The current methodologies for assessing 1p/19q codeletion status are expensive and not widely available. Studies have proposed alpha internexin (INA) expression on immunohistochemistry (IHC) as a surrogate marker for 1p/19q codeletion and a good prognostic marker in gliomas.

Materials and Methods

In this study, we performed IHC for INA expression on the retrospective cohort of anaplastic gliomas (AGs) from our previously published study.

Results

INA positivity on IHC showed a significant positive correlation with 1p/19q codeletion (P < 0.001) with a Spearman's rank correlation coefficient (Rho) of 0.804, sensitivity of 87.5%, specificity of 93.0%, and a diagnostic odds ratio of 93:1 in AGs. Similar to the 1p/19q codeletion status, INA positivity showed a positive correlation with IDHmut (P = 0.002) and a negative correlation with α-thalassemia mental retardation X-linked protein (ATRX) loss of expression (P < 0.001). On univariate survival analysis, INA positivity was associated with significantly prolonged overall survival (OS) and recurrent free survival (RFS) in AGs (P < 0.001). Furthermore, within AO, INA positivity significantly improved RFS (P = 0.022) with OS trending towards significance (P = 0.094).

Conclusions

INA expression on IHC could serve as a potential surrogate marker for 1p/19q, and highlights its prognostic value in AO and AGs.

Clinical and Pathologic Features and Prognostic Factors for Recurrent Gliomas

OBJECTIVE

To explore related factors that influence time to recurrence and prognosis of gliomas.

METHODS

A retrospective analysis of pathologic and clinical data of patients with glioma who underwent surgery for the first time and had a recurrence between 2009 and 2018 in West China Hospital was performed. Clinical characteristics of patients were reviewed, and survival analysis was performed to identify prognostic factors for the recurrent time. Molecules with differential changes in the paired samples were included in the survival analysis.

RESULTS

A total of 84 patients met our inclusion requirements and were included in the study; other related factors were also considered in detail in the integrated analysis. Significant differences among O⁶-methylguanine-DNA methyltransferase (positive/negative), isocitrate dehydrogenase 1 (positive/negative), and Ki-67 were determined by statistical analysis of paired samples (P = 0.013, P = 0.014, P = 0.017). Univariate analysis demonstrated that Ki-67 (low expression, medium expression, high expression), initial World Health Organization grade (low or high), tumor side (left, right, middle), age (≥50 years, <50 years), and extent of resection were significantly correlated with time to recurrence (log-rank P = 0.008, P < 0.001, P = 0.015, P < 0.001, P = 0.001). Multivariate analysis results showed that Ki-67 lower expression (hazard ratio [HR] = 0.585, 95% confidence interval [CI] = 0.146-2.336, P = 0.448), medium expression (HR = 0.256, 95% CI = 0.084-0.784, P = 0.017), and high expression (HR = 1 as a reference) together with the initial World Health Organization grade (HR = 0.148, 95% CI = 0.029-0.749, P = 0.021) were independent predictive factors for glioma recurrence.

CONCLUSIONS

This comprehensive analysis revealed that initial World Health Organization grade and Ki-67 proliferative index were independent prognostic factors that predict the time to recurrence of glioma in patients after first surgery.

The regulator of calcineurin 1 (RCAN1) inhibits nuclear factor kappaB signaling pathway and suppresses human malignant glioma cells growth

Nuclear factor-kappaB (NF-κB) has a vital role in cell survival and inhibition of NF-κB had proven to be an efficient therapeutic pathway for various cancers though little is known about the underlying mechanism. Previously we identified regulator of calcineurin 1 (RCAN1) as an endogenous inhibitor of NF-κB signaling pathway in lymphoma. In the present study, we have solid data to show that RCAN1 can inhibit the nuclear translocation of NF-κB protein then affect the activity of NF-κB signaling pathway in glioma cells. Overexpression of RCAN1 markedly reduced glioma cells viability. We further found that the suppressing glioma cell growth was closely related to the pro-apoptosis effect, not by inhibiting proliferation by the arrest of cell cycle. Our study implicated a novel therapeutic approach for glioma by RCAN1 through inhibition of NF-κB signaling.

Overexpression of NIMA-related kinase 2 is associated with poor prognoses in malignant glioma

Eleated expression of NIMA-related kinase 2 (NEK2) was frequently observed in a variety of malignant cancers, and it appears to be involved in the initiation, maintenance, progression, metastasis of cancer and is positively associated with poor prognosis. We sought to investigate NEK2 expression and its predictive roles in malignant gliomas, and study the correlation of NEK2 protein expression with proliferation, clinical parameters, overall survival and some other parameters. We investigate NEK2 protein expression in 99 samples of malignant gliomas, including 35 WHO grade II, 22 grade III, and 42 grade IV gliomas, by immunohistochemistry and western blot (n = 50). We then made correlative analysis of protein overexpression using the Kaplan-Meier method, Log rank test, and Cox proportional-hazards model analysis. NEK2 protein was overexpressed in malignant gliomas, but not in normal brain tissues. Overexpression of NEK2 correlated with malignancy, proliferation and adverse overall survival in gliomas. Moreover, chemotherapy, resection extent and WHO grade also correlate with overall survival in gliomas. However, within WHO grade II glioma subgroup, NEK2 overexpression showed no impact on overall survival. The present study firstly reveals that NEK2 protein is widely overexpressed in gliomas. NEK2 overexpression correlates significantly with malignancy (WHO grades), proliferation (Ki-67) and prognosis in malignant gliomas. NEK2 is a potential gene therapy target and prognostic indicator.

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.

The overexpression of epithelial cell adhesion molecule (EpCAM) in glioma

Epithelial cell adhesion molecule (EpCAM) is overexpressed in various neoplasms as a tumor-associated antigen and absent in natural brain. However, little is known about EpCAM's expression in gliomas. To investigate the expression of EpCAM in gliomas and understand the correlation of EpCAM expression with malignancy, proliferation, angiogenesis, and prognosis, we studied the expression of EpCAM in 98 glioma samples by immunohistochemistry and by western blotting (N = 12). Correlative analysis of EpCAM overexpression with microvessel density (MVD), Ki-67 expression, age, and gender were made. Survival data was analyzed with Kaplan-Meier method and Cox Proportional Hazard Model. Immunohistochemistry results showed EpCAM was widely expressed in glioma (90.8 %). The overexpression rate of WHO grade IV gliomas was significantly higher EpCAM overexpression correlated significantly with Ki-67 expression and MVD. Western blot analysis also revealed a stepwise increase in EpCAM expression from WHO II to IV glioma. The overall survival of WHO III and IV glioma patients with EpCAM overexpression was obviously lower than that without EpCAM overexpression. EpCAM overexpression was an independent prognostic factor for overall survival in glioma patients. This study firstly shows that EpCAM overexpression correlates significantly with malignancy (WHO grades), proliferation (Ki67), angiogenesis (MVD), and prognosis in gliomas. EpCAM may participate in tumorgenesis of gliomas.

A prognostic model based on preoperative MRI predicts overall survival in patients with diffuse gliomas

BACKGROUND AND PURPOSE

Diffuse gliomas are classified as grades II-IV on the basis of histologic features, with prognosis determined mainly by clinical factors and histologic grade supported by molecular markers. Our aim was to evaluate, in patients with diffuse gliomas, the relationship of relative CBV and ADC values to overall survival. In addition, we also propose a prognostic model based on preoperative MR imaging findings that predicts survival independent of histopathology.

MATERIALS AND METHODS

We conducted a retrospective analysis of the preoperative diffusion and perfusion MR imaging in 126 histologically confirmed diffuse gliomas. Median relative CBV and ADC values were selected for quantitative analysis. Survival univariate analysis was made by constructing survival curves by using the Kaplan-Meier method and comparing subgroups by log-rank probability tests. A Cox regression model was made for multivariate analysis.

RESULTS

The study included 126 diffuse gliomas (median follow-up of 14.5 months). ADC and relative CBV values had a significant influence on overall survival. Median overall survival for patients with ADC < 0.799 × 10(-3) mm(2)/s was <1 year. Multivariate analysis revealed that patient age, relative CBV, and ADC values were associated with survival independent of pathology. The preoperative model provides greater ability to predict survival than that obtained by histologic grade alone.

CONCLUSIONS

ADC values had a better correlation with overall survival than relative CBV values. A preoperative prognostic model based on patient age, relative CBV, and ADC values predicted overall survival of patients with diffuse gliomas independent of pathology. This preoperative model provides a more accurate predictor of survival than histologic grade alone.

Leptomeningeal and intramedullary metastases of glioblastoma multiforme in a patient reoperated during adjuvant radiochemotherapy

Despite huge advances in medicine, glioblastoma multiforme (GBM) remains a highly lethal, fast-growing tumour that cannot be cured by currently available therapies. However, extracranial and extraneural dissemination of GBM is extremely rare, but is being recognised in different imaging studies. To date, the cause of the GBM metastatic spread still remains under discussion. It probably develops at the time of intracranial progression following a surgical procedure. According to other hypothesis, the metastases are a consequence of spontaneous tumour transdural extension or haematogenous dissemination. We present a case of a 59-year-old woman with symptomatic leptomeningeal and intramedullary metastases of GBM who has been previously surgically treated with primary subtotal resection and underwent a repeated surgery during adjuvant radiotherapy and chemotherapy with temozolomide. Today, the main goal of surgery and chemoradiotherapy is to prevent neurologic deterioration and improve health-related quality of life. With this paper, we want to present this rare entity and emphasise the importance of a multidisciplinary approach, a key function in the management of brain tumour patients. The prognosis is still very poor although prolongation of survival can be obtained. Finally, although rare, our case strongly suggests that clinicians should be familiar with the possibility of the extracranial spread of GBM because as treatment improvements provide better control of the primary tumour and improving survival, metastatic disease will be increasingly encountered.

The renal v-ATPase a4 subunit is expressed in specific subtypes of human gliomas

Vacuolar H(+) -ATPases (v-ATPases) are multimeric proton pumps which acidify various intra-cellular organelles and may participate in pHe and pHi regulation in cancer cell lines. The ATP6V0A4 gene encodes the a4 subunit which is expressed in kidney and epididymis. Because we found a4 mRNA highly expressed in C6Bu1 glioma cell line, we measured it in 205 glioma biopsies and 11 brain biopsies from epileptic patients. a4 was absent in epileptic brain biopsies, but was expressed by 34% (11/32) of grade III oligodendrogliomas, independently of the chromosome 1p19q codeletion. a4 expression in grade III oligodendrogliomas and oligoastrocytomas without the 1p19q codeletion tended to be associated with a shorter overall survival of patients. We also observed a4 expression in biopsies of pilocytic astrocytomas (68%; 19/28) and gangliogliomas (37%; 6/16). In pilocytic astrocytomas a4 expression was associated with a tandem duplication of the 7q34 chromosome region, distant 0.5 Mb to the ATP6V0A4 gene locus. In conclusion, a4 expression identifies subtypes of oligodendrogliomas, pilocytic astrocytomas and gangliogliomas and may contribute to refine characterization of these tumors. © 2012 Wiley Periodicals, Inc.

The three-layer concentric model of glioblastoma: cancer stem cells, microenvironmental regulation, and therapeutic implications

Tumors arising in the central nervous system are thought to originate from a sub-population of cells named cancer stem cells (CSCs) or tumor initiating cells (TICs) that possess an immature phenotype, combined with self-renewal and chemotherapy resistance capacity. Moreover, in the last years, these cells have been identified in particular brain tumor niches fundamental for supporting their characteristics. In this paper, we report studies from many authors demonstrating that hypoxia or the so called “hypoxic niche” plays a crucial role in controlling CSC molecular and phenotypic profile. We recently investigated the relationship existing between Glioblastoma (GBM) stem cells and their niche, defining the theory of three-concentric layers model for GBM mass. According to this model, GBM stem cells reside preferentially within the hypoxic core of the tumour mass, while more differentiated cells are mainly localized along the peripheral and vascularized part of the tumour. This GBM model provides explanation of the effects mediated by the tumour microenvironment on the phenotypic and molecular regulation of GBM stem cells, describing their spatial distribution in the tumor bulk. Moreover, we discuss the possible clinical implications of the creation of this model for future GBM patient management and novel therapeutic strategies development.

Non-invasive detection of 2-hydroxyglutarate and other metabolites in IDH1 mutant glioma patients using magnetic resonance spectroscopy

Mutations of the isocitrate dehydrogenase 1 and 2 genes (IDH1 and IDH2) are commonly found in primary brain cancers. We previously reported that a novel enzymatic activity of these mutations results in the production of the putative oncometabolite, R(-)-2-hydroxyglutarate (2-HG). Here we investigated the ability of magnetic resonance spectroscopy (MRS) to detect 2-HG production in order to non-invasively identify patients with IDH1 mutant brain tumors. Patients with intrinsic glial brain tumors (n = 27) underwent structural and spectroscopic magnetic resonance imaging prior to surgery. 2-HG levels from MRS data were quantified using LC-Model software, based upon a simulated spectrum obtained from a GAMMA library added to the existing prior knowledge database. The resected tumors were then analyzed for IDH1 mutational status by genomic DNA sequencing, Ki-67 proliferation index by immunohistochemistry, and concentrations of 2-HG and other metabolites by liquid chromatography-mass spectrometry (LC-MS). MRS detected elevated 2-HG levels in gliomas with IDH1 mutations compared to those with wild-type IDH1 (P = 0.003). The 2-HG levels measured in vivo with MRS were significantly correlated with those measured ex vivo from the corresponding tumor samples using LC-MS (r (2) = 0.56; P = 0.0001). Compared with wild-type tumors, those with IDH1 mutations had elevated choline (P = 0.01) and decreased glutathione (P = 0.03) on MRS. Among the IDH1 mutated gliomas, quantitative 2-HG values were correlated with the Ki-67 proliferation index of the tumors (r ( 2 ) = 0.59; P = 0.026). In conclusion, water-suppressed proton ((1)H) MRS provides a non-invasive measure of 2-HG in gliomas, and may serve as a potential biomarker for patients with IDH1 mutant brain tumors. In addition to 2-HG, alterations in several other metabolites measured by MRS correlate with IDH1 mutation status.

Molecular heterogeneity in glioblastoma: therapeutic opportunities and challenges

Glioblastoma (GBM) has been recognized as a clinical and pathologic entity for more than a century. Throughout its history, its cells of origin have been in question. Its behavior is aggressive and despite decades of effort, median survival is just beginning to improve. Surgical techniques and radiotherapy schemas continue to be refined, but the most recent progress has been achieved through improved medical therapies. These are the result of both pharmacological advances and a deeper understanding of the biological characteristics of GBM. Due to a combination of its complex phenotype and organ-specific clinical manifestations, efforts to refine GBM treatment with targeted therapies largely have been frustrated. In this review, we discuss recent attempts to exploit new molecular insights, consider the reasons for slow progress in developing better treatments, and examine future therapeutic options.