The prognostic value of tumor markers in patients with glioblastoma multiforme: analysis of 32 patients and review of the literature

Low expression of Ki-67/MIB-1 labeling index in IDH wild type glioblastoma predicts prolonged survival independently by MGMT methylation status

PURPOSE

The Ki-67/MIB-1 labeling index (LI) is clinically used to differentiate between high and low-grade gliomas, while its prognostic value remains questionable. Glioblastoma (GBM) expressing wild-type isocitrate dehydrogenase IDH^wt, a relatively common malignant brain tumor in adults, is characterized by a dismal prognosis. Herein, we have retrospectively investigated the prognostic role of Ki-67/MIB-1-LI in a large group of IDH^wt GBM.

METHODS

One hundred nineteen IDH^wt GBM patients treated with surgery followed by Stupp's protocol in our Institution between January 2016 and December 2021 were selected. A cut-off value for Ki-67/MIB-1-LI was used with minimal p-value based approach.

RESULTS

A multivariate analysis showed that Ki-67/MIB-1-LI expression < 15% significantly correlated with a longer overall survival (OS), independently from the age of the patients, Karnofsky performance status scale, extent of surgery and O⁶-methylguanine (O6-MeG)-DNA methyltransferase promoter methylation status.

CONCLUSIONS

Among other studies focused on Ki-67/MIB-1-LI, this is the first observational study showing a positive correlation between OS of IDH^wt GBM patients and Ki-67/MIB-1-LI that we propose as a new predictive marker in this subtype of GBM.

Endoglin (CD105) and proliferation index in recurrent glioblastoma treated with anti-angiogenic therapy

Introduction

CD105 is an angiogenic biomarker that is useful to determine the microvessel density (MVD) within a tumor, namely, in highly vascularized tumors like glioblastoma (GBM). However, its expression has shown inconsistent associations with the prognosis of GBM patients. The aim of this study was to evaluate the value of MVD-CD105 (microvessel density assessed with anti-CD105 antibody) and Ki-67 (proliferation index marker) as prognostic and therapy response biomarkers, specifically in primary tumors and in recurrent tumoral specimens of a cohort of GBM patients treated with bevacizumab upon recurrence.

Materials and methods

We conducted a retrospective study of 102 consecutive GBM patients treated with bevacizumab upon recurrence at CHUSJ between 2010 and 2017. Demographic, clinical, and survival data of all patients were collected and analyzed. The tissue expression of MVD-CD105 and Ki-67 in primary and recurrent specimens was correlated with progression-free survival after temozolomide (PFS-1), progression-free survival after bevacizumab (PFS-2), and overall survival (OS).

Results

The immunohistochemical expression score for MVD-CD105 was similar in primary and recurrent tumoral specimens (mean scores of 15 and 16, respectively). Likewise, the mean Ki-67 expression was similar in primary (mean of 31% of tumor cells) and recurrent tumoral specimens (mean of 29% of tumor cells). MVD-CD105 expression in primary tumors had no impact on PFS-1, PFS-2, or OS. At recurrence, patients whose tumors showed increased MVD-CD105 had worse median PFS-2 (2 vs. 8 months, p = 0.045) and OS (17 vs. 26 months, p = 0.007) compared to those whose tumors showed lower MVD-CD105. CD105 tumoral pattern and localization had no impact on prognosis. Ki-67 expression was not associated with differences in survival outcomes.

Conclusion

In this study, higher MVD-CD105 expression in recurrent GBM patients seems to be associated with a worse PFS-2 and OS while portending no prognostic significance in the primary tumors. This highlights the importance of keeping track of the molecular evolution of the tumor over the course of the disease.

Prognostic impact of PDGFRA gain/amplification and MGMT promoter methylation status in patients with IDH wild-type glioblastoma

Background

Platelet-derived growth factor receptor alpha (PDGFRA) is the second most frequently mutated tyrosine kinase receptor in glioblastoma (GBM). However, the prognostic impact of PDGFRA amplification on GBM patients remains unclear. Herein, we evaluated this impact by retrospectively analyzing outcomes of patients with IDH wild-type GBM.

Methods

Using a custom-made oncopanel, we evaluated PDGFRA gain/amplification in 107 GBM samples harboring wild-type IDH, along with MGMT promoter (MGMTp) methylation status.

Results

We detected PDGFRA gain/amplification in 31 samples (29.0%). PDGFRA gain/amplification predicted poor prognosis (P = .003). Compared to unamplified PDGFRA, PDGFRA gain/amplification in GBM was associated with higher patient age (P = .031), higher Ki-67 score (P = .019), and lower extent of surgical resection (P = .033). Unmethylated MGMTp also predicted poor prognosis (P = .005). As PDGFRA gain/amplification and unmethylated MGMTp were independent factors for poor prognosis in multivariate analyses, we grouped GBM cases based on PDGFRA and MGMTp status: poor (PDGFRA gain/amplification and unmethylated MGMTp), intermediate (PDGFRA gain/amplification or unmethylated MGMTp), and good (PDGFRA intact and methylated MGMTp) prognosis. The Kaplan-Meier survival analysis indicated that these groups significantly correlated with the OS of GBM patients (P < .001).

Conclusions

Here we report that PDGFRA gain/amplification is a predictor of poor prognosis in IDH wild-type GBM. Combining PDGFRA gain/amplification with MGMTp methylation status improves individual prognosis prediction in patients with IDH wild-type GBM.

Is Ki-67 index overexpression in IDH wild type glioblastoma a predictor of shorter Progression Free survival? A clinical and Molecular analytic investigation

BACKGROUND

Ki-67 proliferation index is widely used for differentiating between high and low-grade gliomas, but differentiating between the same grade IV appears to be more problematic, and the point about its prognostic value for GBM patients remains unclear. To reduce the possibility to find a marked histological heterogeneity, and may contain areas that could be diagnosed as lower grade, in this study we considered a large group of patients with IDH wild-type Glioblastoma (IDH-WT GBM) and we have analyzed previously reported prognostic factors, in regards to their relationship with the Ki-67 expression index.

METHODS

We explore the prognostic impact of ki-67 index status in 127 patients affected by IDH-WT GBM. We therefore analyzed clinical characteristics, tumor genetics, dimension and clinical outcomes. We selected a total of 127 patients affected by newly diagnosed IDH-WT GBM who underwent surgery, radiation, and chemotherapy in our Institution in the period ranging between January 2014 and December 2016 RESULTS: The volume of the lesion had a strong association with the Ki67 overexpression. In particular lesions whose volume was greater than 45  cm³, presented a higher percentage of Ki67 expression demonstrating that greater tumors are more likely associated to higher values of Ki67 percentages. On a multivariate analysis, it was possible to outline that Ki67 was significant a predictor of shorter PFS independently from the age of the patients, the volume of the lesion and preoperative KPS.

CONCLUSIONS

There is a correlation between percentage staining of Ki-67 and OS in our cohort of patients with IDH-WT GBM. This is only the third observational study documenting a positive correlation between Ki-67 and overall survival in GBM and the first one demonstrates that percentage Ki-67 staining >20 % predicts poorer progression free survival in IDH-WT GBM.

Cerebellar glioblastoma multiforme in an adult patient with neurofibromatosis type 1: an extremely rare report with review of literature

Background

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder with autosomal dominant inheritance which predisposes the affected individuals to increased risk of developing certain benign and malignant central nervous system (CNS) tumors. NF1 patients are most notably prone to develop low-grade optic pathway, brainstem, and cerebellar astrocytoma. Current literature suggests that brain tumors in patients with NF1 tend to be less aggressive compared to sporadic ones. Glioblastoma multiforme (GBM) is a high-grade glioma which is relatively rare in patients with NF1 and is most commonly seen in supratentorial regions of the brain.

Case presentation

A 33-year-old patient was admitted in neurosurgery ward with acute hydrocephalus caused by a cerebellar mass lesion. On primary assessment, the patient was diagnosed with NF1. He was followed for 2 months and underwent surgical resection of the mass due to worsening symptoms. The pathology report revealed the malignant nature of the lesion. Patient received adjuvant chemo-radiotherapy with diagnosis of cerebellar GBM. Up to 19 months following surgery, he had gained a relatively well ability to walk and talk again.

PROGNOSTIC ROLE OF CD44 EXPRESSION AND NEOVASCULARIZATION DETERMINED BY ENDOGLIN (CD105) IN GLIOBLASTOMA PATIENTS

Glioblastoma multiforme (GBM) is the most common and most aggressive malignant primary brain tumor in humans. Clinically useful molecular markers that help predict response to therapy and prognosis are still rare. The research was conducted in 55 patients with GBM, 26 (47.3%) women and 29 (52.7%) men, mean age 62.58 years. On immunohistochemical analysis, primary antibody to CD44 (dilution 1:50) and primary antibody to endoglin (CD105) (dilution 1:250) were used to evaluate neovascularization. Statistical analysis showed negative correlation between CD44 and survival (p=0.023) (higher expression of CD44 was correlated with shorter survival), but there was no correlation between neovascularization determined by CD105 in GBM and patient survival. Thus, significant individual predictors of longer survival were lower expression of CD44 (p=0.004), higher Karnofsky score (p=0.045), and female gender (p=0.017). The results obtained suggested the possible role of CD44 in the progression and tumor neovascularization of GBM.

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.

Imaging of Tumor Characteristics and Molecular Pathways With PET: Developments Over the Last Decade Toward Personalized Cancer Therapy

PURPOSE

Improvements in personalized therapy are made possible by the advances in molecular biology that led to developments in molecular imaging, allowing highly specific in vivo imaging of biological processes. Positron emission tomography (PET) is the most specific and sensitive imaging technique for in vivo molecular targets and pathways, offering quantification and evaluation of functional properties of the targeted anatomy.

MATERIALS AND METHODS

This work is an integrative research review that summarizes and evaluates the accumulated current status of knowledge of recent advances in PET imaging for cancer diagnosis and treatment, concentrating on novel radiotracers and evaluating their advantages and disadvantages in cancer characterization. Medline search was conducted, limited to English publications from 2007 onward. Identified manuscripts were evaluated for most recent developments in PET imaging of cancer hypoxia, angiogenesis, proliferation, and clonogenic cancer stem cells (CSC).

RESULTS

There is an expansion observed from purely metabolic-based PET imaging toward antibody-based PET to achieve more information on cancer characteristics to identify hypoxia, proangiogenic factors, CSC, and others. ⁶⁴Cu-ATSM, for example, can be used both as a hypoxia and a CSC marker.

CONCLUSIONS

Progress in the field of functional imaging will possibly lead to more specific tumor targeting and personalized treatment, increasing tumor control and improving quality of life.

DCE-MRI prediction of survival time for patients with glioblastoma multiforme: using an adaptive neuro-fuzzy-based model and nested model selection technique

This pilot study investigates the construction of an Adaptive Neuro-Fuzzy Inference System (ANFIS) for the prediction of the survival time of patients with glioblastoma multiforme (GBM). ANFIS is trained by the pharmacokinetic (PK) parameters estimated by the model selection (MS) technique in dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data analysis, and patient age. DCE-MRI investigations of 33 treatment-naïve patients with GBM were studied. Using the modified Tofts model and MS technique, the following physiologically nested models were constructed: Model 1, no vascular leakage (normal tissue); Model 2, leakage without efflux; Model 3, leakage with bidirectional exchange (influx and efflux). For each patient, the PK parameters of the three models were estimated as follows: blood plasma volume (v_p ) for Model 1; v_p and volume transfer constant (K^trans ) for Model 2; v_p , K^trans and rate constant (k_ep ) for Model 3. Using Cox regression analysis, the best combination of the estimated PK parameters, together with patient age, was identified for the design and training of ANFIS. A K-fold cross-validation (K = 33) technique was employed for training, testing and optimization of ANFIS. Given the survival time distribution, three classes of survival were determined and a confusion matrix for the correct classification fraction (CCF) of the trained ANFIS was estimated as an accuracy index of ANFIS's performance. Patient age, k_ep and v_e (K^trans /k_ep ) of Model 3, and K^trans of Model 2, were found to be the most effective parameters for training ANFIS. The CCF of the trained ANFIS was 84.8%. High diagonal elements of the confusion matrix (81.8%, 90.1% and 81.8% for Class 1, Class 2 and Class 3, respectively), with low off-diagonal elements, strongly confirmed the robustness and high performance of the trained ANFIS for predicting the three survival classes. This study confirms that DCE-MRI PK analysis, combined with the MS technique and ANFIS, allows the construction of a DCE-MRI-based fuzzy integrated predictor for the prediction of the survival of patients with GBM.

Cerebrospinal Fluid (Vascular Endothelial Growth Factor) and Serologic (Recoverin) Tumor Markers for Malignant Glioma

BACKGROUND

Clinically useful tumor markers have yet to be identified for malignant glioma. We report on two potential novel tumor markers, vascular endothelial growth factor (VEGF) and recoverin (protein A). VEGF is a highly specific endothelial cell activator that induces angiogenesis both in vivo and in vitro. Our study was designed to assess whether VEGF could be measured in the cerebrospinal fluid (CSF) of patients with cerebral neoplasms and used as a marker of particular tumors. We also studied serum recoverin levels in patients with various brain tumors and compared these to controls. Recoverin is a detectable serologic protein that is expressed in patients with cancer-associated retinopathy, a paraneoplastic syndrome.

METHODS

In the VEGF arm, we used a solid-phase ELISA to determine the levels of VEGF. CSF samples from patients with anaplastic astrocytoma and glioblastoma multiforme (GBM) and with metastatic and nonastrocytic brain tumors were compared with nontumor control samples. In our recoverin study, an immunoenzymetric assay was used to measure the serum recoverin levels patients with glioma and compared with controls.

RESULTS

In the VEGF arm, 89% of samples with malignant astrocytoma and 27% of nonastrocytoma samples had detectable levels of VEGF. VEGF was not detectable in normal CSF samples. The levels of VEGF were significantly higher in high-grade astrocytomas than in nonastrocytic tumors. Recoverin levels were 10-fold higher in patients with recurrent GBM relative to controls. In patients with low-grade glioma, anaplastic glioma, and GBM with no evidence of recurrence, a 3- to 5-fold increase was observed.

CONCLUSIONS

VEGF is detectable in CSF and may be a potential marker for differentiating astrocytic from nonastrocytic tumors. Recoverin is detectable in serum and may be a useful glioma tumor marker, especially for recurrent active disease. These markers may have application for tumor diagnosis, surveillance, and treatment response.

Correlation Between Ki-67 Index, World Health Organization Grade and Patient Survival in Glial Tumors With Astrocytic Differentiation

Background

Glioblastoma multiforme (GBM) is a class IV astrocytic tumor, the most malignant of the four groups of World Health Organization (WHO) tumors with astrocytic differentiation.

Aim

The aim of this study was to estab­lish whether a correlation exists between the Ki-67 index of tumors with astrocytic differentiation, WHO grade, and patient survival.

Materials and methods

A retrospective non-clinical approach to patient selection was chosen for the aim of the study. A total of 47 patients diagnosed and treated for CNS tumors with astrocytic differentiation in the St. Marina University Hospital, Varna, Bulgaria, from September 2012 to July 2016 were retrospectively included into the study cohort. The cases were tested for their immunohistochemistry (IHC) reaction with Ki-67 after their original Hematoxylin and Eosin and IHC slides were reviewed by a single author and blind coded. The Ki-67 positivity index of the nuclei was estimated after digitalization of the slides and calculated by the ImmunoRatio automated count­ing tool. The individual Ki-67 index and patient survival of each case were statistically compared.

Results

The histopathological groups, after the blind Ki-67 index automated calculation was carried out, revealed no WHO grade I, two WHO grade II samples, four WHO grade III samples and 41 WHO grade IV cases, and these were included in the analysis. The two samples of WHO grade II astrocytic tumors had a mean Ki-67 index of 25%; however, they comprised tumors with an individual index of 43% and 7%, both individual values with a highly unlikely index for this group. The four samples of WHO grade III had a mean Ki-67 index of 4%, standard deviation ±2.16 (p>0.05), with the lowest index being 1% and the highest one being 6%. Both WHO grade II and III did not include enough samples to allow for a proper statistical analysis of patient survival. The 41 GBM cases had a mean Ki-67 index of 17.34%, standard deviation ±10.79 (p>0.05). Statistical analysis of the Ki-67 index divid­ed dichotomously into two groups and patient survival revealed that cases with a high Ki-67 index had no significant difference in survival when compared to those with low expression.

Conclusions

Based on the reported results, the mean Ki-67 percentage of positive nuclei in GBM tumor sam­ples cannot be used to estimate the survival of patients. However, Ki-67 remains a valuable IHC pathological tool.

Protein Analysis of Glioblastoma Primary and Posttreatment Pairs Suggests a Mesenchymal Shift at Recurrence

Glioblastomas (GBM) are aggressive brain tumors that inevitably recur despite surgical resection, chemotherapy, and radiation. The degree to which recurrent GBM retains its initial immunophenotype is incompletely understood. We generated tissue microarrays of paired initial and posttreatment GBM (3 pairs positive and 17 negative for IDH1^R132H) from the same patients and made comparisons in the IDH1^R132H-negative group for immunohistochemical and gene expression differences between primary and recurrent tumors. In initial tumors, immunopositivity for Ki-67 in > 20% of tumor cells was associated with shorter progression-free and overall survival. Recurrent tumors showed decreased staining for CD34 suggesting lower vessel density. A subset of tumors showed increased staining for markers associated with the mesenchymal gene expression pattern, including CD44, phosphorylated STAT3, and YKL40. Recurrent tumors with the greatest increase in mesenchymal marker expression had rapid clinical progression, but no difference in overall survival after second surgery. Comparison of protein and gene expression data from the same samples revealed a poor correlation. A subset of tumors (15%) showed loss of neurofibromin protein in both initial and recurrent tumors. These data support the notion that GBM progression is associated with a shift toward a mesenchymal phenotype in a subset of tumors and this may portend a more aggressive behavior.

Ki-67 is a valuable prognostic factor in gliomas: evidence from a systematic review and meta-analysis

Ki-67 has been widely used as an indicator of cell proliferation in gliomas. However, the role of Ki-67 as a prognostic marker is still undefined. Thus, we conducted a meta-analysis of the published literatures in order to clarify the impact of Ki-67 on survival in glioma cases. Eligible studies were identified in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, Science Direct and Wiley Online Library with the last search updated on August 31, 2014. The clinical characteristics, overall survival (OS) and progression- free survival (PFS) together with Ki-67 expression at different time points were extracted. A total of 51 studies, covering 4,307 patients, were included in the current meta-analysis. The results showed that overexpression of Ki-67 can predict poor OS (HR=1.66, 95%CI: 1.53-1.80; Z=11.87; p=0.000) and poor PFS (HR=1.67, 95%CI: 1.47-1.91; Z=7.67; p=0.000) in gliomas. Moreover, subgroup analyses also indicated that high level of Ki-67 expression was related to poor OS and PFS in glioma patients regardless of region, pathology type, cut-off value and statistical method. In conclusion, the current meta-analysis revealed that Ki-67 expression might be a predicative factor for poor prognosis of glioma patients, emphasizing its importance as a predictor.

Proliferation Index Predicts Survival after Second Craniotomy within 6 Months of Adjuvant Radiotherapy for High-grade Glioma

AIMS

To determine pathological features that predict survival in patients having repeat craniotomy within 6 months of radiotherapy for high-grade glioma (HGG).

MATERIALS AND METHODS

HGG patients (World Health Organization grade 3/4) managed with repeat craniotomy within 6 months of completing radiotherapy between 2008 and 2012 were included. Based on the presence of residual tumour cells, the pathology was reported as pathological progression or pathological pseudoprogression. The proliferation index (Ki67) was reported and compared with initial pathology as a percentage change. Tumour necrosis was estimated as a percentage of the specimen. Overall survival was calculated in months.

RESULTS

Of 327 patients managed with HGG, 27 patients underwent repeat craniotomy within 6 months of radiotherapy. The median survival after reoperation was 11 months (95% confidence interval 1-22). Ki67 at reoperation of 0%, 1-9% and >10% was associated with survival with a median survival of 13, 13 and 3 months, respectively (P = 0.007). Change in Ki67 was also associated with median survival, with <50% reduction median survival 3 months, 50-80% median survival 7 months and >80% reduction median survival 13 months, P = 0.02. Widespread treatment-related necrosis improved outcome, with >80% necrosis having a median survival of 13 months versus 3 months in those with <80% necrosis (P = 0.003).

CONCLUSION

The presence of residual tumour at repeat craniotomy within 6 months of radiotherapy is not an independent indicator of prognosis. Patients with residual tumour that had a low Ki67 had a similar median survival as those with only treatment necrosis. Reduced proliferation of residual tumour cells and widespread necrosis may be more important indicators for future outcome.

Pre- and Posttreatment Glioma: Comparison of Amide Proton Transfer Imaging with MR Spectroscopy for Biomarkers of Tumor Proliferation

PURPOSE

To correlate and compare diagnostic performance with amide proton transfer (APT) imaging as a tumor proliferation index with that with magnetic resonance (MR) spectroscopy in subgroups of patients with pre- and posttreatment glioma.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. In 40 patients with pretreatment glioma and 25 patients with posttreatment glioma, correlation between APT asymmetry and the choline-to-creatine and choline-to-N-acetylaspartate ratios in corresponding voxels of interest was determined, and the 90% histogram cutoff of APT asymmetry values (APT90) for the entire solid portion of gliomas was calculated for diagnostic performance. Area under the receiver operating characteristic curve (AUC), leave-one-out cross validation, and intraclass correlation coefficients were analyzed.

RESULTS

The APT asymmetry values showed a moderate correlation (r = 0.49, P < .001) with the choline-to-creatine ratios and a mild correlation with the choline-to-N-acetyl-aspartate ratios (r = 0.32, P = .011) in the corresponding lesions. The APT90 showed comparable diagnostic accuracy for grading of gliomas (AUC, 0.81-0.84 vs 0.86; P = .582-.864) and superior accuracy for differentiation of tumor progression from treatment-related change (AUC, 0.89-0.90 vs 0.60; P = .031-.046) compared with those with MR spectroscopy. The cross-validated area under the curve and accuracy of the APT90 in posttreatment gliomas were 0.89-0.90 and 72%, respectively. The interreader agreement for APT90 was excellent in both pretreatment and posttreatment gliomas (intraclass correlation coefficient, 0.95 and 0.96, respectively).

CONCLUSION

APT imaging used as a tumor proliferation index showed moderate correlation with MR spectroscopic values and is a superior imaging method to MR spectroscopy, particularly for assessment of posttreatment gliomas.

The impact of TP53 and RAS mutations on cerebellar glioblastomas

Cerebellar glioblastoma (cGBM) is a rare, inadequately characterized disease, without detailed information on its molecular basis. This is the first report analyzing both TP53 and RAS alterations in cGBM. TP53 mutations were detected in more than half of the samples from our cohort, mainly in hotspot codons. There were no activating mutations in hotspot codons 12/13 and 61 of KRAS and HRAS genes in cGBM samples but we detected alterations in other parts of exons 2 and 3 of these genes, including premature induction of STOP codon. This mutation was present in 3 out of 5 patients. High incidence of RAS mutations, as well as significantly longer survival of cGBM patients compared to those with supratentorial GBM suggest that cGBM may have different mechanisms of occurrence. Our results suggest that inactivation of TP53 and RAS may play an important role in the progression of cerebellar GBM.

Increased tryptophan uptake on PET has strong independent prognostic value in patients with a previously treated high-grade glioma

BACKGROUND

Previously, we demonstrated the high accuracy of alpha-[(11)C]methyl-L-tryptophan (AMT) PET for differentiating recurrent gliomas from radiation injury. The present study evaluated the prognostic value of increased AMT uptake in patients with previously treated high-grade glioma.

METHODS

AMT-PET was performed in 39 patients with suspected recurrence of World Health Organization grades III-IV glioma following surgical resection, radiation, and chemotherapy. Mean and maximum standardized uptake values (SUVs) and unidirectional AMT uptake (K) were measured in brain regions suspicious for tumor and compared with the contralateral cortex (ie, background). Optimal cutoff thresholds for 1-year survival prediction were determined for each AMT parameter and used for calculating the prognostic value of high (above threshold) versus low (below threshold) values for post-PET overall survival (OS).

RESULTS

In univariate analyses, 1-year survival was strongly associated with 3 AMT parameters (SUVmax, SUVmean, and tumor-to-background K-ratio; odds ratios: 21.3-25.6; P ≤ .001) and with recent change in MRI contrast enhancement (odds ratio: 14.7; P = .02). Median OS was 876 days in the low- versus 177 days in the high-AMT groups (log-rank P < .001). In multivariate analyses, all 3 AMT parameters remained strong predictors of survival: high AMT values were associated with unfavorable 1-year survival (binary regression P ≤ .003) and shorter overall survival in the whole group (Cox regression hazard ratios: 5.3-10.0) and in patients with recent enhancement change on MRI as well (hazard ratios: 7.0-9.3; P ≤ .001).

CONCLUSION

Increased AMT uptake on PET is highly prognostic for 1-year and overall survival, independent of MRI contrast enhancement and other prognostic factors in patients with a previously treated high-grade glioma.

Does gender matter in glioblastoma?

BACKGROUND The clinical outcome of glioblastoma (GBM) patients who receive radiotherapy alone or with chemotherapy is well established. However, little is known about how many patients do not receive this treatment. We consider it is important to investigate why a proportion of operated patients do not receive further treatment after surgery. METHODS We reviewed all consecutive GBM patients operated on in our hospital between January 2000 and December 2008. RESULTS A total of 216 patients with GBM were identified. Fifty-five (25%) did not receive any treatment after surgery. Univariate analysis showed that factors associated with no further treatment after surgery were older than 60 years (p=0.002), of female gender (p=0.03), had a KPS<70 (p<0.001) and had had a biopsy (p<0.001). Multivariate analysis indicated that age =60 years and KPS <70 were independent predictors of no further treatment after surgery. Gender was not an independent variable. However, women in the whole series were older than 60 years (p=0.01), and they had a worse KPS (p=0.02) and more biopsies (p=0.04) than men. In the whole group, median survival time was 10.4 months for men (n=125) vs. 7.2 months for women (n=91), log rank p<0.04. This difference was not observed in the group that was treated after surgery. CONCLUSIONS One out of four patients could not be treated after surgery. Independent predictors were older age and low KPS. These poor risk variables were more frequent in women and their survival was therefore lower than men in our series.

Vaccines for glioblastoma and high-grade glioma

Vaccination by administering tumor antigen plus cell-free or cellular adjuvant has garnered hope for more effective, less toxic therapy for patients with malignant brain tumors including glioblastoma multiforme. To determine if this approach demonstrates ample clinical promise, all published reports of vaccination for glioma were evaluated. These reports suggest vaccination is associated with low toxicity and favorable clinical outcomes. The possibility of selection bias is evident in many published vaccine trials, but several of the more recent ones appropriately attempt to account for bias. Effective induction of antitumor immunity is consistently observed, and, in the latest trials, correlates with significant clinical improvement.

Clinico-pathological feature of pilomyxoid astrocytomas: three case reports

Pilomyxoid astrocytoma (PMA) is a newly identified variant of pilocytic astrocytoma (PA). We report three cases of PMA with comparison to seven cases of PA in terms of their clinicopathological features. The three cases occurred at the ages of 2, 36 and 6 years, and their tumors were located in the left basal ganglia, the pineal gland, and the cerebellum, respectively. They were diagnosed PMA by surgical specimens that showed a characteristic monomorphous architecture with an angiocentric growth pattern and myxoid background. One patient developed localized relapse at 6 months after the surgery, but the other patients remained alive without tumor progression more than 5 years after treatment. In analysis of the immunohistochemical association in PMA and PA, no specific staining was found to be useful for differential diagnosis of PMA from PA. The expression of biomarkers including O-6-methylguanine-DNA methyltransferase, p53, MIB-1, and EGF receptor neither distinguished PMA from PA nor correlated with outcome. But almost all PMA and PA that demonstrated prominent positivity for nestin showed a high MIB-1 labelling index (LI), and four of these five patients suffered a relapse in the early phase. These results suggest that immunohistochemical expression of nestin and MIB-1 LI may correlate with the aggressiveness of the tumor in PA and PMA.

CD133+ niches and single cells in glioblastoma have different phenotypes

Putative CD133(+) brain tumor stem cells have been shown to be located in niches and as single cells. This is the first study providing insight into the different phenotypes of CD133(+) cells in glioblastoma according to localization. Paraffin sections were stained by double immunofluorescence with CD133 and the candidate stem cell markers Sox2, Bmi-1, EGFR, podoplanin and nestin, the proliferation marker Ki67 and the endothelial cell markers CD31, CD34, and VWF. Cell counting showed that the CD133(+) cells in the niches had a significantly higher expression of Sox2, EGFR and nestin compared to CD133(+) single cells, but only a 3% Ki67 labeling index versus 14% found for CD133(+) single cells. Only low endothelial cell marker expression was found in the niches or the CD133(-) tumor areas, while 43% CD133(+)/CD31(+) and 25% CD133(+)/CD34(+) single cells were found. CD133(+) blood vessels within CD133(+) niches were less proliferative and more often Bmi-1(+) than CD133(+) blood vessels outside niches. In conclusion, different CD133(+) cell phenotypes exist according to the in situ localization, and also the phenotype of CD133(+) blood vessels vary according to the localization. CD133(+) niches contain stem-like cells with a lower proliferation index than CD133(+) single cells, which have an endothelial differentiation profile suggesting a role in angiogenesis.

Imaging the life and death of tumors in living subjects: Preclinical PET imaging of proliferation and apoptosis

Cancer is characterized by deregulation of cell proliferation and altered cell death apoptosis, which constitutes, in almost all instances, the minimal common platform upon which all neoplastic evolution occurs. The most implicit and clinically attractive anticancer strategies, therefore, consist of eliminating tumor cells by preventing their expansion and ultimately inducing cell death apoptosis. In this context, the non-invasive molecular assessment of tumor cell proliferation and apoptosis status using PET imaging constitutes a major strategy in preclinical studies to assess the efficacy of new anticancer therapeutics using small animal PET imaging, and in clinical settings for the monitoring of treatment responses in patients. For this purpose, a variety of PET tracers targeting specific molecular entities allowing the non-invasive measurement of biological processes, including cell proliferation and apoptosis, are under development for use in preclinical studies and clinical trials to non-invasively image in vivo the lifeline of tumors.

Tumor regrowth between surgery and initiation of adjuvant therapy in patients with newly diagnosed glioblastoma

To assess incidence and degree of regrowth in glioblastoma between surgery and radiation therapy (RT) and to correlate regrowth with presurgical imaging and survival, we examined images of 32 patients with newly diagnosed glioblastoma who underwent MR spectroscopic imaging (MRSI), perfusion-weighted imaging (PWI), and diffusion-weighted imaging (DWI) prior to surgery, after surgery, and prior to RT/temozolomide. Contrast enhancement (CE) in the pre-RT MR image was compared with postsurgical DWI to differentiate tumor growth from postsurgical infarct. MRSI and PWI parameters were analyzed prior to surgery and pre-RT. Postsurgical MRI indicated that 18 patients had gross total and 14 subtotal resections. Twenty-one patients showed reduced diffusion, and 25 patients showed new or increased CE. In eight patients (25%), the new CE was confined to areas of postsurgical reduced diffusion. In the other 17 patients (53%), new CE was found to be indicative of tumor growth or a combination of tumor growth and surgical injury. Higher perfusion and creatine within nonenhancing tumor in the presurgery MR were associated with subsequent tumor growth. High levels of choline and reduced diffusion in pre-RT CE suggested active metabolism and tumor cell proliferation. Median survival was 14.6 months in patients with interim tumor growth and 24 months in patients with no growth. Increased volume or new onset of CE between surgery and RT was attributed to tumor growth in 53% of patients and was associated with shorter survival. This suggests that reducing the time between surgery and adjuvant therapy may be important. The acquisition of metabolic and physiologic imaging data prior to adjuvant therapy may also be valuable in assessing regions of new CE and nonenhancing tumor.

Hyperpolarized 13C magnetic resonance metabolic imaging: application to brain tumors

In order to compare in vivo metabolism between malignant gliomas and normal brain, (13)C magnetic resonance (MR) spectroscopic imaging data were acquired from rats with human glioblastoma xenografts (U-251 MG and U-87 MG) and normal rats, following injection of hyperpolarized [1-(13)C]-pyruvate. The median signal-to-noise ratio (SNR) of lactate, pyruvate, and total observed carbon-13 resonances, as well as their relative ratios, were calculated from voxels containing Gadolinium-enhanced tissue in T(1) postcontrast images for rats with tumors and from normal brain tissue for control rats. [1-(13)C]-labeled pyruvate and its metabolic product, [1-(13)C]-lactate, demonstrated significantly higher SNR in the tumor compared with normal brain tissue. Statistical tests showed significant differences in all parameters (P < .0004) between the malignant glioma tissue and normal brain. The SNR of lactate, pyruvate, and total carbon was observed to be different between the U-251 MG and U-87 MG models, which is consistent with inherent differences in the molecular characteristics of these tumors. These results suggest that hyperpolarized MR metabolic imaging may be valuable for assessing prognosis and monitoring response to therapy for patients with brain tumors.

The expression level of sphingosine-1-phosphate receptor type 1 is related to MIB-1 labeling index and predicts survival of glioblastoma patients

Although there are many reports on the clinical use of the MIB-1 labeling index (LI), which is a measure of proliferative activity in astrocytomas; its significance varies between studies. There are no known molecules that are directly linked to the MIB-1 LI in astrocytomas. We evaluated the clinical value of the MIB-1 LI in our human glioblastoma cases and determined the molecules that possibly influenced the MIB-1 LI. An immunohistochemical study of the MIB-1 protein was performed and MIB-1 LIs of 38 glioblastomas were determined. In the same cases, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor-alpha (PDGFRA), and sphingosine-1-phosphate receptor type 1 (S1P(1)), which are known regulators of glioma cell proliferation, were detected and quantified by quantitative real-time-PCR or western blotting. Kaplan-Meier survival curves for 38 patients with glioblastomas showed that a high MIB-1 LI correlated with poor survival (P < 0.05). Among the molecules tested, only the low expression of S1P(1) was significantly correlated with the high MIB-1 LI in glioblastomas (P < 0.05). Multivariate analysis revealed that the S1P(1) expression level was a significant prognostic factor. Our results indicate that the MIB-1 LI is an important prognostic factor in human glioblastomas. Furthermore, downregulation of S1P(1) expression increases proliferative activity, and thus enhances the malignancy of glioblastomas, resulting in a poor survival.

DCVax-Brain and DC vaccines in the treatment of GBM

BACKGROUND

DCVax-Brain (Northwest Biotherapeutics, Inc., Bethesda, MD, USA) is a personalized treatment for brain tumors. Its approach of administering autologous tumor antigen-bearing dendritic cells (DCs) has garnered hope for more effective and less toxic therapy for patients with malignant brain tumors including glioblastoma multiforme (GBM). DCVax-Brain composition and efficacy are not fully disclosed, although sponsors claim it is poised to critically test clinical DC vaccine efficacy in GBM patients.

OBJECTIVE

This review examines the efficacy of DC vaccine therapy in treating GBM patients. REVIEW QUESTION: To determine if the approach of DC vaccination followed by DCVax-Brain shows ample clinical promise in GBM patients.

SEARCH STRATEGY

All published reports of DC vaccination for GBM and press releases regarding DCVax-Brain findings were evaluated. CRITICAL APPRAISAL OF REPORTS AND SUMMARY OF OUTCOMES: Published DC vaccine trials for high-grade glioma patients suggest favorable clinical outcomes not easily ascribed to non-treatment parameters. Evidence of possible selection bias exists in many reports, but efforts to account for this are evident in the most recent publications.

CONCLUSION

DC vaccine trials provide evidence of low toxicity in GBM patients and effective induction of antitumor immunity in the latest publications correlate with clinical improvements. Preliminary reports on DCVax-Brain clinical outcomes seem to follow these trends.

Association between hyperglycemia and survival in patients with newly diagnosed glioblastoma

PURPOSE

Hyperglycemia has been associated with poor outcomes in many disease states. This retrospective study assessed the association between hyperglycemia and survival in patients with newly diagnosed glioblastoma multiforme (GBM). PATIENTS AND METHODS; Between 1999 and 2004, before the standard use of temozolomide, 191 patients were accrued onto New Approaches to Brain Tumor Therapy CNS Consortium trials with similar eligibility criteria. Time-weighted mean glucose and mean glucocorticoid dose were calculated for each patient using all values collected regularly in follow-up. The primary outcome was survival.

RESULTS

Mean glucose levels ranged between 65 and 459 mg/dL. These were divided into quartiles: quartile one (< 94 mg/dL), quartile two (94 to 109 mg/dL), quartile three (110 to 137 mg/dL), and quartile four (> 137 mg/dL). Median survival times for patients in quartiles one, two, three, and four were 14.5, 11.6, 11.6, and 9.1 months, respectively. The association between higher mean glucose and shorter survival persisted after adjustment for mean daily glucocorticoid dose, age, and baseline Karnofsky performance score (KPS). Compared with patients in the lowest mean glucose quartile, those in quartile two (adjusted hazard ratio [HR], 1.29; 95% CI, 0.85 to 1.96), quartile three (adjusted HR, 1.35; 95% CI, 0.89 to 2.06), and quartile four (adjusted HR, 1.57; 95% CI, 1.02 to 2.40) were at progressively higher risk of dying (P = .041 for trend).

CONCLUSION

In these patients with newly diagnosed GBM and good baseline KPS, hyperglycemia was associated with shorter survival, after controlling for glucocorticoid dose and other confounders. The effect of intensive management of glucocorticoid-related hyperglycemia on survival deserves additional study in patients with GBM.

Prognostic significance of the immunohistochemical expression of O6-methylguanine-DNA methyltransferase, P-glycoprotein, and multidrug resistance protein-1 in glioblastomas

We studied the expression of O(6)-methylguanine-DNA methyltransferase (O(6)-MGMT), P-glycoprotein (Pgp), and multidrug resistance protein-1 (MRP-1) in 23 glioblastomas using RT-PCR, methylation-specific PCR, and immunohistochemistry, and analyzed their association with overall patient survival. Univariate analysis of collected data demonstrated that the expressions of O(6)-MGMT and MRP-1 detected by immunohistochemistry, in addition to the consistent factors, including preoperative Karnofsky performance scale (KPS), radical surgery, and tumor location and extension, were significant prognostic factors for the overall survival (OS) of patients with glioblastoma, who received nimustine (ACNU)-based chemotherapy in association with surgery and radiotherapy. Among them, following multivariate analysis, preoperative KPS, radical surgery, tumor location, and the expression of O(6)-MGMT remained as significant prognostic factors. These findings suggest that immunohistochemical analysis of O(6)-MGMT in patients with glioblastoma can be a useful method to predict the effects of chemotherapy and identify alternative chemotherapeutic regimens for O(6)-MGMT-positive patients.

Dynamic small-animal PET imaging of tumor proliferation with 3'-deoxy-3'-18F-fluorothymidine in a genetically engineered mouse model of high-grade gliomas

3'-Deoxy-3'-(18)F-fluorothymidine ((18)F-FLT), a partially metabolized thymidine analog, has been used in preclinical and clinical settings for the diagnostic evaluation and therapeutic monitoring of tumor proliferation status. We investigated the use of (18)F-FLT for detecting and characterizing genetically engineered mouse (GEM) high-grade gliomas and evaluating the pharmacokinetics in GEM gliomas and normal brain tissue. Our goal was to develop a robust and reproducible method of kinetic analysis for the quantitative evaluation of tumor proliferation.

METHODS

Dynamic (18)F-FLT PET imaging was performed for 60 min in glioma-bearing mice (n = 10) and in non-tumor-bearing control mice (n = 4) by use of a dedicated small-animal PET scanner. A 3-compartment, 4-parameter model was used to characterize (18)F-FLT kinetics in vivo. For compartmental analysis, the arterial input was measured by placing a region of interest over the left ventricular blood pool and was corrected for partial-volume averaging. The (18)F-FLT "trapping" and tissue flux model parameters were correlated with measured uptake (percentage injected dose per gram [%ID/g]) values at 60 min.

RESULTS

(18)F-FLT uptake values (%ID/g) at 1 h in brain tumors were significantly greater than those in control brains (mean +/- SD: 4.33 +/- 0.58 and 0.86 +/- 0.22, respectively; P < 0.0004). Kinetic analyses of the measured time-activity curves yielded independent, robust estimates of tracer transport and metabolism, with compartmental model-derived time-activity data closely fitting the measured data. Except for tracer transport, statistically significant differences were found between the applicable model parameters for tumors and normal brains. The tracer retention rate constant strongly correlated with measured (18)F-FLT uptake values (r = 0.85, P < 0.0025), whereas a more moderate correlation was found between net (18)F-FLT flux and (18)F-FLT uptake values (r = 0.61, P < 0.02).

CONCLUSION

A clinically relevant mouse glioma model was characterized by both static and dynamic small-animal PET imaging of (18)F-FLT uptake. Time-activity curves were kinetically modeled to distinguish early transport from a subsequent tracer retention phase. Estimated (18)F-FLT rate constants correlated positively with %ID/g measurements. Dynamic evaluation of (18)F-FLT uptake offers a promising approach for noninvasively assessing cellular proliferation in vivo and for quantitatively monitoring new antiproliferation therapies.

In vitro drug response and molecular markers associated with drug resistance in malignant gliomas

PURPOSE

Drug resistance in malignant gliomas contributes to poor clinical outcomes. We determined the in vitro drug response profiles for 478 biopsy specimens from patients with the following malignant glial histologies: astrocytoma (n = 71), anaplastic astrocytoma (n = 39), glioblastoma multiforme (n = 259), oligodendroglioma (n = 40), and glioma (n = 69).

EXPERIMENTAL DESIGN

Samples were tested for drug resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), cisplatin, dacarbazine, paclitaxel, vincristine, and irinotecan. Biomarkers associated with drug resistance were detected by immunohistochemistry, including multidrug resistance gene-1, glutathione S-transferase pi (GSTP1), O(6)-methylguanine-DNA methyltransferase (MGMT), and mutant p53.

RESULTS

In vitro drug resistance in malignant gliomas was independent of prior therapy. High-grade glioblastomas showed a lower level of extreme drug resistance than low-grade astrocytomas to cisplatin (11% versus 27%), temozolomide (14% versus 27%), irinotecan (33% versus 53%), and BCNU (29% versus 38%). A substantial percentage of brain tumors overexpressed biomarkers associated with drug resistance, including MGMT (67%), GSTP1 (49%), and mutant p53 (41%). MGMT and GSTP1 overexpression was independently associated with in vitro resistance to BCNU, whereas coexpression of these two markers was associated with the greatest degree of BCNU resistance.

CONCLUSIONS

Assessment of in vitro drug response and profiles of relevant tumor-associated biomarkers may assist the clinician in stratifying patient treatment regimens.

Prognostic factors for anaplastic astrocytomas

Anaplastic astrocytomas (WHO grade III) constitute about 10% of all gliomas. Definitive data on predictive and prognostic factors are lacking for these neoplasms that are considered the most enigmatic entity among the whole spectrum of astrocytic tumors because of their unclear biologic behavior and variable clinical outcome. Currently, only few factors have been identified as useful for prognosis of anaplastic astrocytoma: age and Karnofsky Performance Status. Attempts have been made to identify biological prognostic factors for response to therapy and clinical outcome, as well as potential targets for new therapies. Potential prognostic biomarkers concern tumor suppressor genes on chromosome 9q that are involved in the RB1 pathway; PTEN, the PI3k/Akt/p70s6k cascade, survivin gene, Formylpeptide receptor, minichromosome maintenance protein 3 and genes on chromosome 7. Furthermore, some angiogenic factors (e.g. hypoxia-inducible factor-1alpha, vascular endothelial growth factor and scatter factor/hepatocyte growth factor) and the methylation status of O6-methylguanine-DNA methyltransferase gene (one of the main effectors of DNA repair system) are emerging novel putative determinants of prognosis. Moreover, recent studies on magnetic resonance imaging characteristics give prognostic significance to the presence of necrosis and enhancement. The state of the art pictured here underlie the recent interest on gene expression profile to identify aberrations useful to understand the biologic behavior of astrocytic tumors. Our knowledge in this field is still limited, and remains an issue of great concern.

The clinical value of Ki-67/MIB-1 labeling index in human astrocytomas

The current WHO classification of human astrocytomas has limitations in predicting prognosis and diagnosis, and there is a need for additional factors. Several studies have investigated the clinical value of proliferative activity in these tumors, especially the Ki-67/MIB-1 labeling index (LI). The aim of this study was to review the literature on this topic to get a survey of the current experience. All studies show increasing values of Ki-67/MIB-1 LI with increasing grade of malignancy. Most of them demonstrate that MIB-1 LI differentiates well between diffuse astrocytomas WHO grade II (AII) and anaplastic astrocytomas (AA) and between AII and glioblastomas (GM), but not between AA and GM. There is, however, considerable overlap of indices between the different malignancy groups. Further, in most studies positive correlations between MIB-1 LI and survival are found, though the proposed cut-off values vary substantially between the reports. The studies reviewed report MIB-1 LI as an important prognostic factor in human astrocytomas. Due to the great spread of values between the various tumor grades, however, MIB-1 LI cannot be used as a diagnostic factor alone but should be used in combination with established criteria of histological malignancy. It may be especially useful in cases where histology reveals a low-grade astrocytoma whereas other parameters indicate a more malignant neoplasm. Thus, it is our opinion that MIB-1 LI should be a part of the routine investigation in patients with astrocytic tumors. Until larger multicenter studies based on standardized immunohistopathological procedures have been completed, each laboratory has to establish its own practice.

Discoidin domain receptor-1a (DDR1a) promotes glioma cell invasion and adhesion in association with matrix metalloproteinase-2

Invasion of glioma cells involves the attachment of invading tumor cells to extracellular matrix (ECM), disruption of ECM components, and subsequent cell penetration into adjacent brain structures. Discoidin domain receptor 1 (DDR1) tyrosine kinases constitute a novel family of receptors characterized by a unique structure in the ectodomain (discoidin-I domain). These cell surface receptors bind to several collagens and facilitate cell adhesion. Little is known about DDR1 expression and function in glioblastoma multiforme. In this study we demonstrate that DDR1 is overexpressed in glioma tissues using cDNA arrays, immunohistochemistry and Western blot analysis. Functional comparison of two splice variants of DDR1 (DDR1a and DDR1b) reveal novel differences in cell based glioma models. Overexpression of either DDR1a or DDR1b caused increased cell attachment. However, glioma cells overexpressing DDR1a display enhanced invasion and migration. We also detect increased levels of matrix metalloproteinase-2 in DDR1a overexpressing cells as measured by zymography. Inhibition of MMP activity using MMP inhibitor suppressed DDR1a stimulated cell-invasion. Similarly, an antibody against DDR1 reduced DDR1a mediated invasion as well as the enhanced adhesion of DDR1a and DDR1b overexpressing cells. These results suggest that DDR1a plays a critical role in inducing tumor cell adhesion and invasion, and this invasive phenotype is caused by activation of matrix metalloproteinase-2.

Role of MIB1 in predicting survival in patients with glioblastomas

BACKGROUND

Histologic immunomarkers of cell cycle proteins have been utilized for prognosis in high-grade astrocytic tumors. One such marker, MIB1, an antibody immunoreactive throughout the cell cycle, is predictive of more aggressive disease and poorer prognosis in astrocytomas. An independent role of MIB1 analysis for survival prediction and clinical management within histologic grades has not been clearly proven.

METHODS

This study retrospectively evaluated MIB1 reactivity in tissue samples from 116 patients with glioblastomas on initial medical presentation. Clinical variables considered included gender, age, Karnofsky Performance Scores (KPS), extent of surgical resection, adjuvant radiation and survival.

RESULTS

Univariate and multivariate analyses were used to correlate these variables with MIB1 staining. MIB1 staining does not predict overall survival or response to adjuvant therapy as an independent risk factor.

CONCLUSION

MIB1 labeling does not predict patient survival as an independent variable and does not predict response to additional therapies. Patient survival with glioblastoma was predicted by KPS, age, extent of resection and use of adjuvant radiotherapy.

Antisense oligonucleodes targeting the focal adhesion kinase inhibit proliferation, induce apoptosis and cooperate with cytotoxic drugs in human glioma cells

To examine the role of focal adhesion kinase in human glioma cells, we studied its effects on proliferation and apoptosis using FAK antisense oligonucleotide. U251 MG cells were transfected with ODNs, sense FAK, mismatch FAK and antisense-FAK, respectively. Expression of FAK proteins were detected by Western blots and Immnofluoressence. Cell apoptosis and mitochondrial membrane potential were analyzed by flow cytometry. Caspase-3 activity was measured by spectrofluorometer. MTT assay was used to examine changes in cell proliferation. The protein expression of FAK in U251 MG cells decreased in antisense-FAK ODNs group significantly. Caspase-3 activity increased in cells treated with antisense-FAK and down-regulated when treated with caspase-3 inhibitor. The level of cell apoptosis and loss of mitochondrial membrane potential in antisense-FAK group was higher than in the mismatch sense group. Cells proliferation was inhibited by antisense-FAK, and the effects were clearly additive when antisense oligonuceotides were added to cells treated with the anticancer agents. The results suggest that antisense-FAK ODNs inhibit U251 MG cells proliferation and induce their apoptosis. It is possible that FAK via mitochondrial and caspase-3 inhibits U251 MG cells apoptosis. And antisense oligonucleotide treatment enhances U251 MG cells sensitivity to chemotherapy.

Chromosome 22 tiling-path array-CGH analysis identifies germ-line- and tumor-specific aberrations in patients with glioblastoma multiforme

Gliomas are common and frequently malignant tumors of the central nervous system. Recurrent allelic losses of chromosome 22 have been reported in gliomas, indicating tumor-suppressor genes at this location. However, the target genes are still unknown. We applied a high resolution tiling-path chromosome 22 array to a series of 50 glioblastoma samples, with the aim of investigating the underlying abnormalities in both constitutional and tumor-derived DNA. We detected hemizygous deletions in 28% of the tumors (14 of 50), with monosomy 22 (10 of 50) being the predominant pattern. The distribution of overlapping hemizygous deletions delineated two putative tumor-suppressor loci (11.1 and 3.08 Mb in size) across 22q. Most strikingly, we identified two distinct loci affected by regional gains. Both alterations were of germ-line origin and were unique to samples from patients affected with tumors. Analysis of these two amplified regions revealed the presence of two interesting candidate genes: TOP3B and TAFA5. The TOP3B gene encodes a protein that seems to function in the unlinking of parental strands at the final stage of DNA replication and/or in the dissociation of structures in mitotic cells that could lead to recombination. The TAFA5 gene belongs to a novel family of proteins with similarity to chemokines and brain-specific expression. The role of the identified candidate loci should be studied further. Our results demonstrated the power of array-CGH to determine DNA copy number alterations in the context of germ-line- and tumor-specific aberrations.

Expression of Drug Resistance Proteins Pgp, MRP1, MRP3, MRP5 AND GST-π in Human Glioma

Chemotherapy in glioma is poorly effective: the blood-brain barrier and intrinsic and/or acquired drug resistance of tumor cells could partly explain this lack of major effect. We investigated expression of P-glycoprotein (Pgp), multidrug resistance protein (MRP) 1, MRP3, MRP5 and glutathione-S-transferase pi (GST-pi) in malignant glioma patients. Cytofluorimetric analysis of 48 glioma specimens and 21 primary cultures showed high levels of MRP1, moderate levels of MRP5 and low levels of Pgp, GST-pi and MRP3. Immunohistochemistry (25 glioma specimens) showed expression of GST-pi (66.7% of cases), MRP1 (51.3%), MRP5 (45.8%), Pgp (34.8%) and MRP3 (29.9%) in tumor cells. Moreover, analysis of tumor samples by real time quantitative PCR showed mRNA expression of all investigated genes. Tumor vasculature, analyzed in glioma specimens and in tumor derived endothelial cells, showed expression of all investigated proteins. Non-tumor brain samples (from a patient with arteriovenous malformation and from one with epilepsy), normal human astrocytes and cultured endothelial cells were also analyzed: astrocytes and endothelial cells expressed the highest levels of the investigated proteins, mainly MRP1 and MRP5. No significant differences in proteins expression were detected between primary or recurrent gliomas, suggesting that glioma chemoresistance is mostly intrinsic. Therefore, we detected, for the first time, the presence of MRP3 and MRP5 on glioma specimens--both in tumor and endothelial cells--and we delineated an expression profile of chemoresistance proteins in glioma. The possible association of inhibitors of drug efflux pumps with chemotherapy could be investigated to improve drugs delivery into the tumor and their cytotoxic effects.

Genetic analyses for predictors of radiation response in glioblastoma

PURPOSE

Radiotherapy (RT) for patients with glioblastoma improves survival and is recommended for nearly all patients with this diagnosis. However, the response to RT is variable in this patient population. Prior studies have suggested that underlying genetic alterations in the tumor may account for some of this treatment-related heterogeneity. It has been previously reported that epidermal growth factor receptor (EGFR) gene amplification and TP53 mutation correlate with the response to RT in patients with glioblastoma.

METHODS AND MATERIALS

We sought to identify molecular markers that could predict the response to RT, progression-free survival after RT, and overall survival among 75 glioblastoma patients treated with RT at a single institution. Genetic analyses assessed EGFR amplification, TP53 mutations, CDKN2A/p16 deletion, and losses of chromosomes 1p, 10q, and 19q.

RESULTS

Unlike previous reports, no association of EGFR amplification with response to RT, progression-free survival, or overall survival was found. Moreover, no association was found between these endpoints and the other genetic alterations assayed (TP53 mutation, CDKN2A/p16 deletion, loss of heterozygosity 1p, loss of heterozygosity 10q, and loss of heterozygosity 19q). However, in accordance with recent observations that the prognostic effects of genetic alterations in glioblastoma may depend on patient age, we observed age-dependent prognostic effects of TP53 and CDKN2A/p16 alterations in our patient population. For patients > or = 57 years old, those harboring TP53 mutations had a decreased overall survival compared with patients without TP53 mutations. Similarly, deletion of CDKN2A/p16 in patients > or = 57 years was associated with decreased progression-free survival after RT and a trend toward a shorter time to progression after RT compared with similar patients without the deletion.

CONCLUSION

These data contrast with previous studies regarding the significant prognostic effect of EGFR with respect to RT response. Although our observations regarding the age-dependent prognostic effects of TP53 and CDKN2A/p16 are consistent with a prior report regarding these alterations, the present results should be considered preliminary, given the small sample size.

Clinical responsiveness of glioblastoma multiforme to chemotherapy after vaccination

PURPOSE

Although the development of immune-based therapies for various cancers including malignant glioma has been heralded with much hope and optimism, objective clinical improvements in most vaccinated cancer patients have not been realized. To broaden the search for vaccine-induced benefits, we examined synergy of vaccines with conventional chemotherapy.

EXPERIMENTAL DESIGN

Survival and progression times were analyzed retrospectively in 25 vaccinated (13 with and 12 without subsequent chemotherapy) and 13 nonvaccinated de novo glioblastoma (GBM) patients receiving chemotherapy. Immune responsiveness and T-cell receptor excision circle (TREC) content within CD8+ T cells (CD8+ TRECs) was determined in vaccinated patients.

RESULTS

Vaccinated patients receiving subsequent chemotherapy exhibited significantly longer times to tumor recurrence after chemotherapy relative to their own previous recurrence times, as well as significantly longer postchemotherapy recurrence times and survival relative to patients receiving isolated vaccination or chemotherapy. Patients exhibiting objective (>50%) tumor regression, extremely rare in de novo GBM, were also confined to the vaccine + chemotherapy group. Prior tumor behavior, demographic factors, other treatment variables, distribution of vaccine responders, and patients with high CD8+ TRECs all failed to account for these differences in clinical outcome. Within all GBM patients receiving post-vaccine chemotherapy, however, CD8+ TRECs predicted significantly longer chemotherapeutic responses, revealing a strong link between the predominant T-cell effectors in GBM and tumor chemosensitivity.

CONCLUSIONS

We propose that therapeutic vaccination synergizes with subsequent chemotherapy to elicit tangible clinical benefits for GBM patients.

Contribution of gap junctional communication between tumor cells and astroglia to the invasion of the brain parenchyma by human glioblastomas

Background

Gliomas are "intraparenchymally metastatic" tumors, invading the brain in a non-destructive way that suggests cooperation between glioma cells and their environment. Recent studies using an engineered rodent C6 tumor cell line have pointed to mechanisms of invasion that involved gap junctional communication (GJC), with connexin 43 as a substrate. We explored whether this concept may have clinical relevance by analyzing the participation of GJC in human glioblastoma invasion.

Results

Three complementary in vitro assays were used: (i) seeding on collagen IV, to analyze homocellular interactions between tumor cells (ii) co-cultures with astrocytes, to study glioblastoma/astrocytes relationships and (iii) implantation into organotypic brain slice cultures, that mimic the three-dimensional parenchymal environment. Carbenoxolone, a potent blocker of GJC, inhibited cell migration in the two latter models. It paradoxically increased it in the first one. These results showed that homocellular interaction between tumor cells supports intercellular adhesion, whereas heterocellular glioblastoma/astrocytes interactions through functional GJC conversely support tumor cell migration. As demonstrated for the rodent cell line, connexin 43 may be responsible for this heterocellular functional coupling. Its levels of expression, high in astrocytes, correlated positively with invasiveness in biopsied tumors.

Conclusions

our results underscore the potential clinical relevance of the concept put forward by other authors based on experiments with a rodent cell line, that glioblastoma cells use astrocytes as a substrate for their migration by subverting communication through connexin 43-dependent gap junctions.

Comparative genomic hybridization analysis of astrocytomas: prognostic and diagnostic implications

Astrocytoma is comprised of a group of common intracranial neoplasms that are classified into four grades based on the World Health Organization histological criteria and patient survival. To date, histological grade, patient age, and clinical performance, as reflected in the Karnofsky score, are the most reliable prognostic predictors. Recently, there has been a significant effort to identify additional prognostic markers using objective molecular genetic techniques. We believe that the identification of such markers will characterize new chromosomal loci important in astrocytoma progression and aid clinical diagnosis and prognosis. To this end, our laboratory used comparative genomic hybridization to identify DNA sequence copy number changes in 102 astrocytomas. Novel losses of 19p loci were detected in low-grade pilocytic astrocytomas and losses of loci on 9p, 10, and 22 along with gains on 7, 19, and 20 were detected in a significant proportion of high-grade astrocytomas. The Cox proportional hazards statistical modeling showed that the presence of +7q and -10q comparative genomic hybridization alterations significantly increased a patient's risk of dying, independent of histological grade. This investigation demonstrates the efficacy of comparative genomic hybridization for identifying tumor suppressor and oncogene loci in different astrocytic grades. The cumulative effect of these loci is an important consideration in their diagnostic and prognostic implications.

Loss of the AP-2α Transcription Factor Is Associated with the Grade of Human Gliomas

Purpose: The activator protein (AP)-2α transcription factor plays a crucial role in the progression of several human tumors, including malignant melanoma, prostate, and breast cancer. Loss of AP-2α results in deregulation of several genes with AP-2α binding motifs such as E-cadherin, p21WAF1, MMP-2, MCAM/MUC18, VEGF, and c-KIT. The purpose of our study was to determine AP-2α expression distribution among grades of gliomas and any possible effect on prognosis.

Experimental Design: A tissue microarray was assembled from all surgical glioma cases with available tissue samples at M.D. Anderson Cancer Center since 1986 to include 72 glioblastomas, 49 anaplastic astrocytomas, 9 low-grade astrocytoma, 37 oligodendrogliomas, 37 anaplastic oligodendrogliomas, 15 mixed oligoastrocytomas, 20 anaplastic mixed oligoastrocytomas, and 7 gliosarcomas. The microarray included normal brain tissue, and AP-2α expression was determined by immunohistochemistry.

Results: AP-2α expression was lost on 99% (P &lt; 0.001) and 98% (P &lt; 0.001) of glioblastomas and anaplastic astrocytomas, respectively, compared with grade 2 astrocytomas and normal brain, all of which (100%) maintained expression of AP-2α. The loss of AP-2α was a negative prognostic indicator within the overall category of gliomas by univariate analysis (rate ratio, 4.30; 95% confidence interval, 2.60-7.10; P &lt; 0.001). However, there was no significant effect of loss of AP-2α expression on survival observed after adjustment for patient age, Karnofsky Performance Scale score, tumor grade, and extent of resection (rate ratio, 1.2; 95% confidence interval, 0.6-2.2; P = 0.6).

Conclusions: AP-2α expression correlates inversely with glioma grade, suggesting a direct role in glioma tumorigenicity, possibly through subsequent deregulation of target genes. Of all the previously characterized markers of progression, the loss of AP-2α would be the most common (96.2%) molecular marker as an astrocytic tumor evolves from grade 2 to 3.

Cellular DNA content parameters as prognostic indicators in human astrocytomas

OBJECTIVE

Clinical parameters such as grade, size and/or location of the tumor are good predictors of outcome in patients with astrocytoma. The objective of this study was to determine whether DNA content parameters have a prognostic significance for this group of tumors.

METHODS

Following optimization and validation of methodology for evaluating cellular DNA content parameters (CDCP), tumor DNA ploidy and percent S phase fraction (SPF) were determined from 64 patients using formalin fixed, paraffin embedded specimens (mean coefficient of variation=4.94) obtained over a 10-year period. Median survival times correlated with grade (I/II=1154 vs. III/IV=483days, P=0.0317). Fifty-five percent of the specimens contained DNA aneuploid (DNA-A) components (average SPF=18.3%) and 45% were DNA diploid (DNA-D) (average SPF=9.6%). Survival did not correlate with overall differences in DNA ploidy (DNA-D=181 vs. DNA-A=206days, P=0.6314) when treated and untreated tumors were analyzed. However, a trend for prolonged median survival was observed in patients whose tumors were untreated with respect to cytotoxic therapy based on DNA ploidy status (DNA-D=275 vs. DNA-A=15days, P=0.3408). Survival for all patients did not correlate with median SPF (<13.5% av.=121 vs. >13.5% av.=154days, P=0.6534).

CONCLUSION

DNA content parameters may correlate with the natural history and treatment outcome of newly diagnosed untreated patients with astrocytomas.

Gene expression profiling of gliomas strongly predicts survival

In current clinical practice, histology-based grading of diffuse infiltrative gliomas is the best predictor of patient survival time. Yet histology provides little insight into the underlying biology of gliomas and is limited in its ability to identify and guide new molecularly targeted therapies. We have performed large-scale gene expression analysis using the Affymetrix HG U133 oligonucleotide arrays on 85 diffuse infiltrating gliomas of all histologic types to assess whether a gene expression-based, histology-independent classifier is predictive of survival and to determine whether gene expression signatures provide insight into the biology of gliomas. We found that gene expression-based grouping of tumors is a more powerful survival predictor than histologic grade or age. The poor prognosis samples could be grouped into three different poor prognosis groups, each with distinct molecular signatures. We further describe a list of 44 genes whose expression patterns reliably classify gliomas into previously unrecognized biological and prognostic groups: these genes are outstanding candidates for use in histology-independent classification of high-grade gliomas. The ability of the large scale and 44 gene set expression signatures to group tumors into strong survival groups was validated with an additional external and independent data set from another institution composed of 50 additional gliomas. This demonstrates that large-scale gene expression analysis and subset analysis of gliomas reveals unrecognized heterogeneity of tumors and is efficient at selecting prognosis-related gene expression differences which are able to be applied across institutions.