Konstantinos Gousias

Chromosome 7p11.2 (EGFR) variation influences glioma risk

While gliomas are the most common primary brain tumors, their etiology is largely unknown. To identify novel risk loci for glioma, we conducted genome-wide association (GWA) analysis of two case-control series from France and Germany (2269 cases and 2500 controls). Pooling these data with previously reported UK and US GWA studies provided data on 4147 glioma cases and 7435 controls genotyped for 424 460 common tagging single-nucleotide polymorphisms. Using these data, we demonstrate two statistically independent associations between glioma and rs11979158 and rs2252586, at 7p11.2 which encompasses the EGFR gene (population-corrected statistics, P(c) = 7.72 × 10(-8) and 2.09 × 10(-8), respectively). Both associations were independent of tumor subtype, and were independent of EGFR amplification, p16INK4a deletion and IDH1 mutation status in tumors; compatible with driver effects of the variants on glioma development. These findings show that variation in 7p11.2 is a determinant of inherited glioma risk.

TERT promoter mutations: a novel independent prognostic factor in primary glioblastomas.

BACKGROUND Activating somatic mutations in the promoter region of the telomerase reverse transcriptase gene (TERT) have been detected in several cancers. In this study we investigated the TERT promoter mutations and their impact on patient survival in World Health Organization grade IV glioblastoma multiforme (GBM). METHODS The TERT core promoter region containing the previously described mutations and a common functional polymorphism (rs2853669) was sequenced in tumors and blood samples from 192 GBM patients. O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation status was assessed by pyrosequencing in 177 (92.2%) cases. Relevant clinical data were obtained from a prospectively maintained electronic database. RESULTS We detected specific (-124 C>T and -146 C>T) TERT promoter mutations in 143/178 (80.3%) primary GBM and 4/14 (28.6%) secondary GBM (P < .001). The presence of TERT mutations was associated with poor overall survival, and the effect was confined to the patients who did not carry the variant G-allele for the rs2853669 polymorphism. An exploratory analysis suggested that TERT mutations might be prognostic only in patients who had incomplete resections and no temozolomide chemotherapy. CONCLUSIONS In this study, specific TERT promoter mutations were markers of primary GBM and predicted patient survival in conjunction with a common functional polymorphism. The prognostic impact of TERT mutations was absent in patients with complete resections and temozolomide chemotherapy. If confirmed in additional studies, these findings may have clinical implications, that is, TERT mutations appear to characterize tumors that require aggressive treatment.

TERT Promoter Mutations and Risk of Recurrence in Meningioma

The World Health Organization (WHO) classification and grading system attempts to predict the clinical course of meningiomas based on morphological parameters. However, because of high interobserver variation of some criteria, more reliable prognostic markers are required. Here, we assessed the TERT promoter for mutations in the hotspot regions C228T and C250T in meningioma samples from 252 patients. Mutations were detected in 16 samples (6.4% across the cohort, 1.7%, 5.7%, and 20.0% of WHO grade I, II, and III cases, respectively). Data were analyzed by t test, Fishers exact test, log-rank test, and Cox proportional hazard model. All statistical tests were two-sided. Within a mean follow-up time in surviving patients of 68.1 months, TERT promoter mutations were statistically significantly associated with shorter time to progression (P < .001). Median time to progression among mutant cases was 10.1 months compared with 179.0 months among wild-type cases. Our results indicate that the inclusion of molecular data (ie, analysis of TERT promoter status) into a histologically and genetically integrated classification and grading system for meningiomas increases prognostic power. Consequently, we propose to incorporate the assessment of TERT promoter status in upcoming grading schemes for meningioma.

Genetic Risk Profiles Identify Different Molecular Etiologies for Glioma

Purpose: Genome-wide association studies have recently identified single-nucleotide polymorphisms (SNP) in five loci at 5p15.33 (rs2736100, TERT), 8q24.21 (rs4295627, CCDC26), 9p21.3 (rs4977756, CDKN2A/CDKN2B), 20q13.33 (rs6010620, RTEL1), and 11q23.3 (rs498872, PHLDB1) to be associated with glioma risk. Because gliomas are heterogeneous in histology, molecular alterations, and clinical behavior, we have investigated these polymorphisms for potential correlations with tumor histology and patient survival. Experimental Design: We studied the relationship between SNPs and glioma subtype in two large patient cohorts from France and Germany, totaling 1,577 patients, as well as the relationship between SNP genotype and overall survival. Results: In both cohorts, the frequencies of rs2736100 and rs6010620 risk genotypes were highly correlated with high-grade disease (P < 0.001), whereas rs4295627 and rs498872 risk genotypes were inversely related to tumor grade (P < 0.001). These data show that genetic variations at these loci have subtype-specific effects on the risk of developing glioma. In contrast, the rs4977756 genotype was not correlated with tumor grade, consistent with the causal variant having a generic influence on glioma development. None of the five SNPs was associated with prognosis independent of tumor grade. Conclusions: Our findings provide novel insight into etiologic pathways in the different glioma subtypes. Clin Cancer Res; 16(21); 5252–9. ©2010 AACR.

Genome-wide association study of glioma subtypes identifies specific differences in genetic susceptibility to glioblastoma and non-glioblastoma tumors.

Genome-wide association studies (GWAS) have transformed our understanding of glioma susceptibility, but individual studies have had limited power to identify risk loci. We performed a meta-analysis of existing GWAS and two new GWAS, which totaled 12,496 cases and 18,190 controls. We identified five new loci for glioblastoma (GBM) at 1p31.3 (rs12752552; P = 2.04 × 10−9, odds ratio (OR) = 1.22), 11q14.1 (rs11233250; P = 9.95 × 10−10, OR = 1.24), 16p13.3 (rs2562152; P = 1.93 × 10−8, OR = 1.21), 16q12.1 (rs10852606; P = 1.29 × 10−11, OR = 1.18) and 22q13.1 (rs2235573; P = 1.76 × 10−10, OR = 1.15), as well as eight loci for non-GBM tumors at 1q32.1 (rs4252707; P = 3.34 × 10−9, OR = 1.19), 1q44 (rs12076373; P = 2.63 × 10−10, OR = 1.23), 2q33.3 (rs7572263; P = 2.18 × 10−10, OR = 1.20), 3p14.1 (rs11706832; P = 7.66 × 10−9, OR = 1.15), 10q24.33 (rs11598018; P = 3.39 × 10−8, OR = 1.14), 11q21 (rs7107785; P = 3.87 × 10−10, OR = 1.16), 14q12 (rs10131032; P = 5.07 × 10−11, OR = 1.33) and 16p13.3 (rs3751667; P = 2.61 × 10−9, OR = 1.18). These data substantiate that genetic susceptibility to GBM and non-GBM tumors are highly distinct, which likely reflects different etiology.

Low penetrance susceptibility to glioma is caused by the TP53 variant rs78378222

Background:Most of the heritable risk of glioma is presently unaccounted for by mutations in known genes. In addition to rare inactivating germline mutations in TP53 causing glioma in the context of the Li-Fraumeni syndrome, polymorphic variation in TP53 may also contribute to the risk of developing glioma.Methods:To comprehensively evaluate the impact of variation in TP53 on risk, we analysed 23 tagSNPs and imputed 2377 unobserved genotypes in four series totaling 4147 glioma cases and 7435 controls.Results:The strongest validated association signal was shown by the imputed single-nucleotide polymorphism (SNP) rs78378222 (P=6.86 × 10−24, minor allele frequency ∼0.013). Confirmatory genotyping confirmed the high quality of the imputation. The association between rs78378222 and risk was seen for both glioblastoma multiforme (GBM) and non-GBM tumours. We comprehensively examined the relationship between rs78378222 and overall survival in two of the case series totaling 1699 individuals. Despite employing statistical tests sensitive to the detection of differences in early survival, no association was shown.Conclusion:Our data provided strong validation of rs78378222 as a risk factor for glioma but do not support the tenet that the polymorphism being a clinically useful prognostic marker. Acquired TP53 inactivation is a common feature of glioma. As rs78378222 changes the polyadenylation signal of TP53 leading to impaired 3′-end processing of TP53 mRNA, the SNP has strong plausibility for being directly functional contributing to the aetiological basis of glioma.

The Simpson grading revisited: aggressive surgery and its place in modern meningioma management

OBJECTIVE Recent advances in radiotherapy and neuroimaging have called into question the traditional role of aggressive resections in patients with meningiomas. In the present study the authors reviewed their institutional experience with a policy based on maximal safe resections for meningiomas, and they analyzed the impact of the degree of resection on functional outcome and progression-free survival (PFS). METHODS The authors retrospectively analyzed 901 consecutive patients with primary meningiomas (716 WHO Grade I, 174 Grade II, and 11 Grade III) who underwent resections at the University Hospital of Bonn between 1996 and 2008. Clinical and treatment parameters as well as tumor characteristics were analyzed using standard statistical methods. RESULTS The median follow-up was 62 months. PFS rates at 5 and 10 years were 92.6% and 86.0%, respectively. Younger age, higher preoperative Karnofsky Performance Scale (KPS) score, and convexity tumor location, but not the degree of resection, were identified as independent predictors of a good functional outcome (defined as KPS Score 90-100). Independent predictors of PFS were degree of resection (Simpson Grade I vs II vs III vs IV), MIB-1 index (< 5% vs 5%-10% vs >10%), histological grade (WHO I vs II vs III), tumor size (≤ 6 vs > 6 cm), tumor multiplicity, and location. A Simpson Grade II rather than Grade I resection more than doubled the risk of recurrence at 10 years in the overall series (18.8% vs 8.5%). The impact of aggressive resections was much stronger in higher grade meningiomas. CONCLUSIONS A policy of maximal safe resections for meningiomas prolongs PFS and is not associated with increased morbidity.

Deciphering the 8q24.21 association for glioma

We have previously identified tagSNPs at 8q24.21 influencing glioma risk. We have sought to fine-map the location of the functional basis of this association using data from four genome-wide association studies, comprising a total of 4147 glioma cases and 7435 controls. To improve marker density across the 700 kb region, we imputed genotypes using 1000 Genomes Project data and high-coverage sequencing data generated on 253 individuals. Analysis revealed an imputed low-frequency SNP rs55705857 (P = 2.24 × 10(-38)) which was sufficient to fully capture the 8q24.21 association. Analysis by glioma subtype showed the association with rs55705857 confined to non-glioblastoma multiforme (non-GBM) tumours (P = 1.07 × 10(-67)). Validation of the non-GBM association was shown in three additional datasets (625 non-GBM cases, 2412 controls; P = 1.41 × 10(-28)). In the pooled analysis, the odds ratio for low-grade glioma associated with rs55705857 was 4.3 (P = 2.31 × 10(-94)). rs55705857 maps to a highly evolutionarily conserved sequence within the long non-coding RNA CCDC26 raising the possibility of direct functionality. These data provide additional insights into the aetiological basis of glioma development.

Genome-wide association study identifies multiple susceptibility loci for glioma

Previous genome-wide association studies (GWASs) have shown that common genetic variation contributes to the heritable risk of glioma. To identify new glioma susceptibility loci, we conducted a meta-analysis of four GWAS (totalling 4,147 cases and 7,435 controls), with imputation using 1000 Genomes and UK10K Project data as reference. After genotyping an additional 1,490 cases and 1,723 controls we identify new risk loci for glioblastoma (GBM) at 12q23.33 (rs3851634, near POLR3B, P=3.02 × 10−9) and non-GBM at 10q25.2 (rs11196067, near VTI1A, P=4.32 × 10−8), 11q23.2 (rs648044, near ZBTB16, P=6.26 × 10−11), 12q21.2 (rs12230172, P=7.53 × 10−11) and 15q24.2 (rs1801591, near ETFA, P=5.71 × 10−9). Our findings provide further insights into the genetic basis of the different glioma subtypes.

Frequent abnormalities of the immune system in gliomas and correlation with the WHO grading system of malignancy

AIM To investigate the cellular and humoral immunity status of gliomas, and their association with the WHO grading system. MATERIAL AND METHODS We have conducted a case-control study of 49 patients with gliomas and 30 healthy controls. We used ELISA assays, radial immunodiffusion, indirect immunofluorescence, latex test and flow cytometry assays to estimate preoperative in serum the immunological profile. RESULTS Patients with glioma had significantly reduced amounts of IL2 (p=0.000), TNF-a (p=0.033), IgG (p=0.011), IgA (p=0.027),C4 (p=0.026) ,CD3+ (p=0.001), CD4+ (p=0.000), CD8+ (p=0.002), ratio CD4/CD8 (p=0.000), CD19+ (p=0.04) and elevated IL10 (p=0.05) compared with healthy controls. No statistically significant differences were observed concerning viral agents, total NK cells, IgM, IgE, IL16, granzyme-b, RF, ANA, ENA, anti-dsDNA and anti-cardiolipin antibodies. A higher WHO grade, after controlling for age and gender, was associated with decreased number of CD3+ (p=0.011), CD4+ (p=0.015), CD8+ (p=0.048) and ratio CD4/CD8 (p=0.027), as well as with decreased IL2 (p=0.018), C4 (p=0.02), and IgG (p=0.05). IL2 and CD4+ counts were significant predictors of grade. CONCLUSIONS A shift from Th1 to Th2, a CD3+ and CD19+ lymphocytopenia, a diminished fraction CD4/CD8 and a reduced amount of immunoglobulins and complement were observed in the patients with gliomas. A higher WHO grade of the tumor was associated with greater impairments of immunity. Since defects of both humoral and cellular immunity were equally observed and significant predictors of grade were assessed, a preoperative evaluation of the immune system of patients with gliomas is being proposed.