Michel Wager

Comparative assessment of 5 methods (methylation-specific polymerase chain reaction, methylight, pyrosequencing, methylation-sensitive high-resolution melting, and immunohistochemistry) to analyze O6-methylguanine-DNA-methyltranferase in a series of 100 glioblastoma patients.

There is a strong need to determine the best technique for O6‐methylguanine‐DNA‐methyltranferase (MGMT) analysis, because MGMT status is currently used in clinical trials and occasionally in routine clinical practice for glioblastoma patients.

Oncological patterns of care and outcome for 952 patients with newly diagnosed glioblastoma in 2004

This report, an audit requested by the French government, describes oncological patterns of care, prognostic factors, and survival for patients with newly diagnosed and histologically confirmed glioblastoma multiforme (GBM) in France. The French Brain Tumor DataBase, which is a national multidisciplinary (neurosurgeons, neuropathologists, radiotherapists, neurooncologists, epidemiologists, and biostatisticians) network, prospectively collected initial data for the cases of GBM in 2004, and a specific data card was used to retrospectively collect data on the management and follow-up care of these patients between January 1, 2004, and December 1, 2006. We recorded 952 cases of GBM (male/female ratio 1.6, median age 63.9 years, mean preoperative Karnofsky performance status [KPS] 79). Surgery consisted of resection (RS; n = 541) and biopsy (n = 411); 180 patients did not have subsequent oncological treatment. After surgery, first-line treatment (n = 772) consisted of radiotherapy (RT) and temozolomide (TMZ) concomitant +/- adjuvant in 314 patients, RT alone in 236 patients, chemotherapy (CT) alone in 157 patients, and other treatment modalities in 65 patients. Median overall survival was 286 days (95% CI, 266-314) and was significantly affected by age, KPS, and tumor location. Median survival (days, 95% CI) associated with these main strategies, when analyzed by a surgical group, were as follows: RS + RT-TMZ((n=224)): 476 (441-506), biopsy + RT-TMZ((n=90)): 329 (301-413), RS + RT((n=147)): 363 (331-431), biopsy + RT((n=89)): 178 (153-237), RS + CT((n=61)): 245 (190-361), biopsy + CT((n=96)): 244 (198-280), and biopsy only((n=118)): 55 (46-71). This study illustrates the usefulness of a national brain tumor database. To our knowledge, this work is the largest report of recent GBM management in Europe.

Correlation of clinical features and methylation status of MGMT gene promoter in glioblastomas

In an effort to extend the potential relationship between the methylation status of MGMT promoter and response to CENU therapy, we examined the methylation status of MGMT promoter in 44 patients with glioblastomas. Tumor specimens were obtained during surgery before adjuvant treatment, frozen and stored at −80 °C until for DNA extraction process. DNA methylation patterns in the CpG island of the MGMT gene were determined in every tumor by methylation specific PCR (MSP). These results were then related to overall survival and response to alkylating agents using statistical analysis.Methylation of the MGMT promoter was detected in 68% of tumors, and 96.7% of methylated tumors exhibited also an unmethylated status. There was no relationship between the methylation status of the MGMT promoter and overall survival and response to alkylating agents. Our observations do not lead us to consider promoter methylation of MGMT gene as a prognostic factor of responsiveness to alkylating agents in glioblastomas.

STAT3 is essential for the maintenance of neurosphere‐initiating tumor cells in patients with glioblastomas: A potential for targeted therapy?

Glioblastoma (GBM), the highest‐grade form of gliomas, is the most frequent and the most aggressive. Recently, a subpopulation of cells with stem cells characteristics, commonly named “tumor‐initiating stem cells” (TISCs) or “cancer stem cells” (CSCs) were identified in GBM. These cells were shown to be highly resistant to chemotherapeutic drugs and to ionizing radiations. Consequently, the knowledge of the signals that regulate the functions and survival of TISCs is crucial. In our work, we describe a neurosphere‐initiating cell (NS‐IC) assay to quantify TISC/CSCs from patients with GBM and show that these cells are tumorigenic in vivo. We demonstrate that the intracellular signal transducer and activator of transcription STAT3 is constitutively activated by phosphorylation preferentially on serine 727 in these cells. Moreover, we demonstrate that the selective inhibition of STAT3 by the chemical compound Stattic or by siRNA STAT3 abrogates TISC/CSC proliferation and NS‐IC suggesting that self‐renewal of GBM “stem‐like” cells depends on the presence of STAT3 for their maintenance. Finally, we show that inhibition of STAT3 by Stattic sensitizes TISC/CSCs to the inhibitory action of Temozolomide with a strong synergistic effect of both drugs. Overall, these results suggest that strategies focused on STAT3 inhibition are efficient at the level of “stem‐like” cells and could be of interest for therapeutic purposes in patients with malignant GBM.

Contrast enhancement in 1p/19q-codeleted anaplastic oligodendrogliomas is associated with 9p loss, genomic instability, and angiogenic gene expression

BACKGROUND The aim of this study was to correlate MRI features and molecular characteristics in anaplastic oligodendrogliomas (AOs). METHODS The MRI characteristics of 50 AO patients enrolled in the French national network for high-grade oligodendroglial tumors were analyzed. The genomic profiles and IDH mutational statuses were assessed using high-resolution single-nucleotide polymorphism arrays and direct sequencing, respectively. The gene expression profiles of 25 1p/19q-codeleted AOs were studied on Affymetrix expression arrays. RESULTS Most of the cases were frontal lobe contrast-enhanced tumors (52%), but the radiological presentations of these cases were heterogeneous, ranging from low-grade glioma-like aspects (26%) to glioblastoma-like aspects (22%). The 1p/19q codeletion (n = 39) was associated with locations in the frontal lobe (P = .001), with heterogeneous intratumoral signal intensities (P = .003) and with no or nonmeasurable contrast enhancements (P = .01). The IDH wild-type AOs (n = 7) more frequently displayed ringlike contrast enhancements (P = .03) and were more frequently located outside of the frontal lobe (P = .01). However, no specific imaging pattern could be identified for the 1p/19q-codeleted AO or the IDH-mutated AO. Within the 1p/19q-codeleted AO, the contrast enhancement was associated with larger tumor volumes (P = .001), chromosome 9p loss and CDKN2A loss (P = .006), genomic instability (P = .03), and angiogenesis-related gene expression (P < .001), particularly for vascular endothelial growth factor A and angiopoietin 2. CONCLUSION In AOs, the 1p/19q codeletion and the IDH mutation are associated with preferential (but not with specific) imaging characteristics. Within 1p/19q-codeleted AO, imaging heterogeneity is related to additional molecular alterations, especially chromosome 9p loss, which is associated with contrast enhancement and larger tumor volume.

An ANOCEF genomic and transcriptomic microarray study of the response to radiotherapy or to alkylating first-line chemotherapy in glioblastoma patients.

BackgroundThe molecular characteristics associated with the response to treatment in glioblastomas (GBMs) remain largely unknown. We performed a retrospective study to assess the genomic characteristics associated with the response of GBMs to either first-line chemotherapy or radiation therapy. The gene expression (n = 56) and genomic profiles (n = 67) of responders and non-responders to first-line chemotherapy or radiation therapy alone were compared on Affymetrix Plus 2 gene expression arrays and BAC CGH arrays.ResultsAccording to Verhaak et al.s classification system, mesenchymal GBMs were more likely to respond to radiotherapy than to first-line chemotherapy, whereas classical GBMs were more likely to respond to first-line chemotherapy than to radiotherapy. In patients treated with radiation therapy alone, the response was associated with differential expression of microenvironment-associated genes; the expression of hypoxia-related genes was associated with short-term progression-free survival (< 5 months), whereas the expression of immune genes was associated with prolonged progression-free survival (> 10 months). Consistently, infiltration of the tumor by both CD3 and CD68 cells was significantly more frequent in responders to radiotherapy than in non-responders. In patients treated with first-line chemotherapy, the expression of stem-cell genes was associated with resistance to chemotherapy, and there was a significant association between response to treatment and p16 locus deletions. Consistently, in an independent data set of patients treated with either radiotherapy alone or with both radiotherapy and adjuvant chemotherapy, we found that patients with the p16 deletion benefited from adjuvant chemotherapy regardless of their MGMT promoter methylation status, whereas in patients without the p16 deletion, this benefit was only observed in patients with a methylated MGMT promoter.ConclusionDifferential expression of microenvironment genes and p16 locus deletion are associated with responses to radiation therapy and to first-line chemotherapy, respectively, in GBM. Recently identified transcriptomic subgroups of GBMs seem to respond differently to radiotherapy and to first-line chemotherapy.

Cauda equina tumors: a French multicenter retrospective review of 231 adult cases and review of the literature

Abstract Large series of cauda equina tumors in adults are seldom reported. This French series retrospectively reviews 231 cases collected for the congress of the Société Française de Neurochirurgie in 1996. The authors first analyze this series and then discuss the pertinent literature. Schwannoma was the most frequent benign tumor in this series, followed by ependymoma. Very few malignant tumors were recorded; these were usually malignant neurinomas nearly always in neurofibromatosis patients. Some other rare tumors were also recorded, including paragangliomas. This series confirms the importance of the pretherapeutic neurological status in functional prognosis. All schwannomas can be cured, while ependymomas and paragangliomas may recur after a very long delay. Surgery must be as complete as possible, since adjuvant therapies are proven to have little efficacy. This type of tumor requires very long follow-up. Prognosis is good for hemangioblastomas. Sphincter dysfunctions carries a poor prognosis and may appear after primary surgery, more often after treatment of recurrences.

O6-Methylguanine-Methyltransferase (MGMT) Promoter Methylation Status in Glioma Stem-Like Cells is Correlated to Temozolomide Sensitivity Under Differentiation-Promoting Conditions

Glioblastoma (GBM) is the most malignant type of primary brain tumor with a very poor prognosis. The actual standard protocol of treatment for GBM patients consists of radiotherapy and concomitant temozolomide (TMZ). However, the therapeutic efficacy of this treatment is limited due to tumor recurrence and TMZ resistance. Recently isolated, glioma stem-like cells (GSCs) are thought to represent the population of tumorigenic cells responsible for GBM resistance and recurrence following surgery and chemotherapy. In addition, MGMT (O6-methylguanine-methyltransferase) methylation is considered as one of the principal mechanisms contributing to TMZ sensitivity of GBM. In this study we have isolated GSCs from 10 adult GBM patients and investigated the relationship between MGMT methylation status and Temozolomide (TMZ) sensitivity of these lines grown either in stem-like or differentiation promoting conditions. Sensitivity to TMZ was significantly associated with MGMT methylation status in cells committed to differentiation but not in stem-like cells. In addition, patients harboring highly methylated MGMT promoters had a longer overall survival. These results reveal the importance of the differentiation process when considering the predictive value of MGMT status in GSCs for clinical response to TMZ.

EGFR, KRAS, BRAF, and HER‐2 molecular status in brain metastases from 77 NSCLC patients

The aim of this study was to determine the frequency of EGFR, KRAS, BRAF, and HER‐2 mutations in brain metastases from non‐small cell lung carcinomas (BM‐NSCLC). A total of 77 samples of BM‐NSCLC were included and 19 samples of BM from breast, kidney, and colorectal tumors were also studied as controls. These samples were collected from patients followed between 2008 and 2011 at Poitiers and Nice University Hospitals in France. The frequencies of EGFR, KRAS, BRAF, and HER‐2 mutations in BM‐NSCLC were 2.6, 38.5, 0, and 0% respectively. The incidence of KRAS mutation was significantly higher in female and younger patients (P < 0.05). No mutations of the four genes were found in BM from breast or kidney. However, among six BM from colorectal tumors, we identified KRAS mutations in three cases and BRAF mutations in two other cases. This study is the largest analysis on genetic alterations in BM‐NSCLC performed to date. Our results suggest a low frequency of EGFR mutations in BM‐NSCLC whereas KRAS mutations are as frequent in BM‐NSCLC as in primitive NSCLC. These results raise the question of the variability of the brain metastatic potential of NSCLC cells in relation to the mutation pattern.

Allelic loss of 9p21.3 is a prognostic factor in 1p/19q codeleted anaplastic gliomas

Objectives: We aimed to study the potential clinical relevance of 9p allelic loss, with or without copy number variation, in 1p/19q codeleted anaplastic oligodendroglial tumors (AOTs). Methods: This study enrolled 216 patients with 1p/19q codeleted AOT. The prognostic value of 9p allelic loss was investigated using a French nation-wide prospective registry, POLA (prise en charge des tumeurs oligodendrogliales anaplasiques) and high-density single nucleotide polymorphism arrays. We validated our results using the Repository of Molecular Brain Neoplasia Data (REMBRANDT) dataset. Results: The minimal common region of allelic loss in chromosome arm 9p was 9p21.3. Allelic loss of 9p21.3, detected in 41.7% of tumors, was associated with shorter progression-free and overall survival rates in univariate (p = 0.008 and p < 0.001, respectively) and multivariate analyses (p = 0.009 and p = 0.009, respectively). This finding was validated in the REMBRANDT dataset in univariate and multivariate analysis (p = 0.01 and p = 0.01, respectively). Conclusion: Our study highlights a novel potential prognostic biomarker in 1p/19q codeleted AOT. Further prospective studies are warranted to investigate our finding.