Large- and medium-sized arterial aneurysms in two patients with SMAD4-related juvenile polyposis syndrome.

Germline SMAD4 pathogenic variants (PVs) cause juvenile polyposis syndrome (JPS), which is known for an increased risk of gastrointestinal juvenile polyps and gastrointestinal cancer. Many patients with SMAD4 PV also show signs of hereditary hemorrhagic telangiectasia (HHT) and some patients have aneurysms and dissections of the thoracic aorta. Here we describe two patients with a germline SMAD4 PV and a remarkable clinical presentation including multiple medium-sized arterial aneurysms. More data are needed to confirm whether the more extensive vascular phenotype and the other described features in our patients are indeed part of a broader JPS spectrum.

Delineating genotype and parent-of-origin effect on the phenotype in MSH6-associated Lynch syndrome.

BACKGROUND: This study investigates the potential influence of genotype and parent-of-origin effects (POE) on the clinical manifestations of Lynch syndrome (LS) within families carrying (likely) disease-causing MSH6 germline variants. PATIENTS AND METHODS: A cohort of 1615 MSH6 variant carriers (310 LS families) was analyzed. Participants were categorized based on RNA expression and parental inheritance of the variant. Hazard ratios (HRs) were calculated using weighted Cox regression, considering external information to address ascertainment bias. The findings were cross-validated using the Prospective Lynch Syndrome Database (PLSD) for endometrial cancer (EC). RESULTS: No significant association was observed between genotype and colorectal cancer (CRC) risk (HR = 1.06, 95% confidence interval [CI]: 0.77-1.46). Patients lacking expected RNA expression exhibited a reduced risk of EC (Reference Cohort 1: HR = 0.68, 95% CI: 0.43-1.03; Reference Cohort 2: HR = 0.63, 95% CI: 0.46-0.87). However, these results could not be confirmed in the PLSD. Moreover, no association was found between POE and CRC risk (HR = 0.78, 95% CI: 0.52-1.17) or EC risk (Reference Cohort 1: HR = 0.93, 95% CI: 0.65-1.33; Reference Cohort 2: HR = 0.8, 95% CI: 0.64-1.19). DISCUSSION AND CONCLUSION: No evidence of POE was detected in MSH6 families. While RNA expression may be linked to varying risks of EC, further investigation is required to explore this observation.

Discordant Staining Patterns and Microsatellite Results in Tumors of MSH6 Pathogenic Variant Carriers.

Diagnosis of Lynch syndrome (LS) caused by a pathogenic germline MSH6 variant may be complicated by discordant immunohistochemistry (IHC) and/or by a microsatellite stable (MSS) phenotype. This study aimed to identify the various causes of the discordant phenotypes of colorectal cancer (CRC) and endometrial cancer (EC) in MSH6-associated LS. Data were collected from Dutch family cancer clinics. Carriers of a (likely) pathogenic MSH6 variant diagnosed with CRC or EC were categorized based on an microsatellite instability (MSI)/IHC test outcome that might fail to result in a diagnosis of LS (eg, retained staining of all 4 mismatch repair proteins, with or without an MSS phenotype, and other staining patterns). When tumor tissue was available, MSI and/or IHC were repeated. Next-generation sequencing (NGS) was performed in cases with discordant staining patterns. Data were obtained from 360 families with 1763 (obligate) carriers. MSH6 variant carriers with CRC or EC (n = 590) were included, consisting of 418 CRCs and 232 ECs. Discordant staining was reported in 77 cases (36% of MSI/IHC results). Twelve patients gave informed consent for further analysis of tumor material. Upon revision, 2 out of 3 MSI/IHC cases were found to be concordant with the MSH6 variant, and NGS showed that 4 discordant IHC results were sporadic rather than LS-associated tumors. In 1 case, somatic events explained the discordant phenotype. The use of reflex IHC mismatch repair testing, the current standard in most Western countries, may lead to the misdiagnosis of germline MSH6 variant carriers. The pathologist should point out that further diagnostics for inheritable colon cancer, including LS, should be considered in case of a strong positive family history. Germline DNA analysis of the mismatch repair genes, preferably as part of a larger gene panel, should therefore be considered in potential LS patients.

Identifying the BRCA1 c.-107A > T variant in Dutch patients with a tumor BRCA1 promoter hypermethylation.

An inherited single nucleotide variant (SNV) in the 5'UTR of the BRCA1 gene c.-107A > T was identified to be related to BRCA1 promoter hypermethylation and a hereditary breast and ovarian cancer phenotype in two UK families. We investigated whether this BRCA1 variant was also present in a Dutch cohort of breast and ovarian cancer patients with tumor BRCA1 promoter hypermethylation. We selected all breast and ovarian cancer cases that tested positive for tumor BRCA1 promoter hypermethylation at the Netherlands Cancer Institute and Sanger sequenced the specific mutation in the tumor DNA. In total, we identified 193 tumors with BRCA1 promoter hypermethylation in 178 unique patients. The wild-type allele was identified in 100% (193/193) of sequenced tumor samples. In a large cohort of 178 patients, none had tumors harboring the previously identified c.-107A > T SNV in BRCA1. We therefore can conclude that the germline SNV is not pervasive in patients with tumor BRCA1 promoter hypermethylation.

Clinical value of a screening tool for tumor predisposition syndromes in childhood cancer patients (TuPS): a prospective, observational, multi-center study.

Recognizing a tumor predisposition syndrome (TPS) in a child with cancer is of clinical relevance. Earlier we developed a screening tool to increase diagnostic accuracy and clinical efficiency of identifying TPSs in children with cancer. Here we report on the value of this tool in clinical practice. TuPS is a prospective, observational, multi-center study including children newly diagnosed with cancer from 2016 to 2019 in the Netherlands. Children in whom a TPS had been diagnosed before the cancer diagnosis were excluded. The screening tool consists of a checklist, 2D and 3D photographic series and digital assessment of these by a clinical geneticist. If a TPS was suspected, the patient was assessed positive and referred for routine genetic consultation. Primary aim was to assess the clinical value of this new screening tool. Of the 363 included patients, 57% (208/363) were assessed positive. In 15% of patients (32/208), the 2D photographic series with (n = 12) or without (n = 20) 3D photographs were decisive in the positive assessment. In 2% (4/208) of positive assessed patients, a TPS was diagnosed, and in an additional 2% (4/208) a germline variant of uncertain significance was found. Thirty-five negatively assessed patients were evaluated through routine genetic consultation as controls, in none a TPS was detected. Using the screening tool, 57% of the patients were assessed as suspected for having a TPS. No false negative results were identified in the negative control group in the clinical care setting. The observed prevalence of TPS was lower than expected, due to selection bias in the cohort.

Families with BAP1-Tumor Predisposition Syndrome in The Netherlands: Path to Identification and a Proposal for Genetic Screening Guidelines.

Germline pathogenic variants in the BRCA1-associated protein-1 (BAP1) gene cause the BAP1-tumor predisposition syndrome (BAP1-TPDS, OMIM 614327). BAP1-TPDS is associated with an increased risk of developing uveal melanoma (UM), cutaneous melanoma (CM), malignant mesothelioma (MMe), renal cell carcinoma (RCC), meningioma, cholangiocarcinoma, multiple non-melanoma skin cancers, and BAP1-inactivated nevi. Because of this increased risk, it is important to identify patients with BAP1-TPDS. The associated tumors are treated by different medical disciplines, emphasizing the need for generally applicable guidelines for initiating genetic analysis. In this study, we describe the path to identification of BAP1-TPDS in 21 probands found in the Netherlands and the family history at the time of presentation. We report two cases of de novo BAP1 germline mutations (2/21, 9.5%). Findings of this study combined with previously published literature, led to a proposal of guidelines for genetic referral. We recommend genetic analysis in patients with ≥2 BAP1-TPDS-associated tumors in their medical history and/or family history. We also propose to test germline BAP1 in patients diagnosed with UM <40 years, CM <18 years, MMe <50 years, or RCC <46 years. Furthermore, other candidate susceptibility genes for tumor types associated with BAP1-TPDS are discussed, which can be included in gene panels when testing patients.

Somatic mosaicism by a de novo MLH1 mutation as a cause of Lynch syndrome.

BACKGROUND: Lynch syndrome (LS) is caused by germline mismatch repair (MMR) gene mutations. De novo MMR gene mutations are rare, and somatic mosaicism in LS is thought to be infrequent. We describe the first case of somatic mosaicism by a de novo MLH1 mutation for a patient diagnosed with a rectosigmoid adenocarcinoma at age 31. METHODS: Twelve years after initial colorectal cancer diagnosis, tumor tissue of the patient was tested with sensitive next generation sequencing (NGS) analysis for the presence of somatic MMR mutations. RESULTS: In tumor tissue, an inactivating MLH1 mutation (c.518_519del; p.(Tyr173Trpfs*18)) was detected, which was also present at low level in the blood of the patient. In both parents, as well as the patient's sisters, the mutation was not present. CONCLUSION: We show that low-level mosaicism can be detected by using high-coverage targeted NGS panels on constitutional and/or tumor DNA. This report illustrates that by using sensitive sequencing techniques, more cases of genetic diseases driven by mosaic mutations may be identified, with important clinical consequences for patients and family members.

Information exchange between patients with Lynch syndrome and their genetic and non-genetic health professionals: whose responsibility?

Individuals at high risk for Lynch syndrome (LS) should be offered genetic counselling, since preventive options are available. However, uptake of genetic services and follow-up care are currently suboptimal, possibly caused by inadequate exchange of information. Therefore, this qualitative study aims to gain insight in the process of information exchange between patients diagnosed with LS and their non-genetic (i.e., general practitioner, gastroenterologist, gynaecologist) and genetic (i.e., clinical geneticist or genetic counsellor) health professionals concerning referral for genetic counselling and follow-up care. Participants comprised 13 patients diagnosed with LS (8 index patients and 5 of their affected relatives) and 24 health professionals (6 general practitioners, 8 gastroenterologists, 6 gynaecologists and 4 genetic health professionals). Analysis of the interview transcripts was performed in parallel and again after the interviews, following guidelines for qualitative research and using MAXQDA software. The main finding is that patients may 'get lost' between health professionals who lack a clear overview of their own and each other's role and responsibilities in the referral and follow-up care for patients with possible LS. Education of non-genetic health professionals and optimisation of communication between health professionals might help to enable more timely diagnosis of LS and allow patients to address their doubts and questions to the most appropriate healthcare professional.

IDH1/2 Mutations Sensitize Acute Myeloid Leukemia to PARP Inhibition and This Is Reversed by IDH1/2-Mutant Inhibitors.

Purpose: Somatic mutations in IDH1/2 occur in approximately 20% of patients with myeloid neoplasms, including acute myeloid leukemia (AML). IDH1/2MUT enzymes produce D-2-hydroxyglutarate (D2HG), which associates with increased DNA damage and improved responses to chemo/radiotherapy and PARP inhibitors in solid tumor cells. Whether this also holds true for IDH1/2MUT AML is not known.Experimental Design: Well-characterized primary IDH1MUT, IDH2MUT, and IDH1/2WT AML cells were analyzed for DNA damage and responses to daunorubicin, ionizing radiation, and PARP inhibitors.Results:IDH1/2MUT caused increased DNA damage and sensitization to daunorubicin, irradiation, and the PARP inhibitors olaparib and talazoparib in AML cells. IDH1/2MUT inhibitors protected against these treatments. Combined treatment with a PARP inhibitor and daunorubicin had an additive effect on the killing of IDH1/2MUT AML cells. We provide evidence that the therapy sensitivity of IDH1/2MUT cells was caused by D2HG-mediated downregulation of expression of the DNA damage response gene ATM and not by altered redox responses due to metabolic alterations in IDH1/2MUT cells.Conclusions:IDH1/2MUT AML cells are sensitive to PARP inhibitors as monotherapy but especially when combined with a DNA-damaging agent, such as daunorubicin, whereas concomitant administration of IDH1/2MUT inhibitors during cytotoxic therapy decrease the efficacy of both agents in IDH1/2MUT AML. These results advocate in favor of clinical trials of PARP inhibitors either or not in combination with daunorubicin in IDH1/2MUT AML. Clin Cancer Res; 24(7); 1705-15. ©2018 AACR.

Childhood tumours with a high probability of being part of a tumour predisposition syndrome; reason for referral for genetic consultation.

INTRODUCTION: Recognising a tumour predisposition syndrome (TPS) in childhood cancer patients is of major clinical relevance. The presence of a TPS may be suggested by the type of tumour in the child. We present an overview of 23 childhood tumours that in themselves should be a reason to refer a child for genetic consultation. METHODS: We performed a PubMed search to review the incidence of TPSs in children for 85 tumour types listed in the International Classification of Childhood Cancer third edition (ICCC-3). The results were discussed during a national consensus meeting with representative clinical geneticists from all six academic paediatric oncology centres in The Netherlands. A TPS incidence of 5% or more was considered a high probability and therefore in itself a reason for referral to a clinical geneticist. RESULTS: The literature search resulted in data on the incidence of a TPS in 26 tumours. For 23/26 tumour types, a TPS incidence of 5% or higher was reported. In addition, during the consensus meeting the experts agreed that children with any carcinoma should always be referred for clinical genetic consultation as well, as it may point to a TPS. CONCLUSION: We present an overview of 23 paediatric tumours with a high probability of a TPS; this will facilitate paediatric oncologists to decide which patients should be referred for genetic consultation merely based on type of tumour.

Validation of a clinical screening instrument for tumour predisposition syndromes in patients with childhood cancer (TuPS): protocol for a prospective, observational, multicentre study.

INTRODUCTION: Recognising a tumour predisposition syndrome (TPS) in patients with childhood cancer is of significant clinical relevance, as it affects treatment, prognosis and facilitates genetic counselling. Previous studies revealed that only half of the known TPSs are recognised during standard paediatric cancer care. In current medical practice it is impossible to refer every patient with childhood cancer to a clinical geneticist, due to limited capacity for routine genetic consultation. Therefore, we have developed a screening instrument to identify patients with childhood cancer with a high probability of having a TPS. The aim of this study is to validate the clinical screening instrument for TPS in patients with childhood cancer. METHODS AND ANALYSIS: This study is a prospective nationwide cohort study including all newly diagnosed patients with childhood cancer in the Netherlands. The screening instrument consists of a checklist, two- and three-dimensional photographic series of the patient. 2 independent clinical geneticists will assess the content of the screening instrument. If a TPS is suspected based on the instrument data and thus further evaluation is indicated, the patient will be invited for full genetic consultation. A negative control group consists of 20% of the patients in whom a TPS is not suspected based on the instrument; they will be randomly invited for full genetic consultation. Primary outcome measurement will be sensitivity of the instrument. ETHICS AND DISSEMINATION: The Medical Ethical Committee of the Academic Medical Centre stated that the Medical Research Involving Human Subjects Act does not apply to this study and that official approval of this study by the Committee was not required. The results will be offered for publication in peer-reviewed journals and presented at International Conferences on Oncology and Clinical Genetics. The clinical data gathered in this study will be available for all participating centres. TRIAL REGISTRATION NUMBER: NTR5605.

Type 1 papillary renal cell carcinoma in a patient with schwannomatosis: Mosaic versus loss of SMARCB1 expression in respectively schwannoma and renal tumor cells.

In schwannomatosis, germline SMARCB1 or LZTR1 mutations predispose to the development of multiple benign schwannomas. Besides these, other tumors may occur in schwannomatosis patients. We present a 45-year-old male patient who developed multiple schwannomas and in addition a malignant type 1 papillary renal cell carcinoma (pRCC1). We identified a duplication of exon 7 of SMARCB1 on chromosome 22 in the constitutional DNA of the patient (c.796-2246_986 + 5250dup7686), resulting in the generation of a premature stop codon in the second exon 7 copy (p.Glu330*). The mutant SMARCB1 allele proved to be retained in three schwannomas and in the pRCC1 of the patient. Loss of heterozygosity analysis demonstrated partial loss of the wild-type SMARCB1 allele containing chromosome 22, suggesting loss of that chromosome in only a subset of tumor cells, in all four tumors. Immunohistochemical staining with a SMARCB1 antibody revealed a mosaic SMARCB1 expression pattern in the three benign schwannomas, but absence of expression in the malignant tumor cells of the pRCC1. To our knowledge, this difference in SMARCB1 protein expression has not been reported before. We conclude that a germline SMARCB1 mutation may predispose to the development of pRCC1, thereby further widening the spectrum of tumors that can develop in the context of schwannomatosis.

Radioprotection of IDH1-Mutated Cancer Cells by the IDH1-Mutant Inhibitor AGI-5198.

Isocitrate dehydrogenase 1 (IDH1) is mutated in various types of human cancer to IDH1(R132H), a structural alteration that leads to catalysis of α-ketoglutarate to the oncometabolite D-2-hydroxyglutarate. In this study, we present evidence that small-molecule inhibitors of IDH1(R132H) that are being developed for cancer therapy may pose risks with coadministration of radiotherapy. Cancer cells heterozygous for the IDH1(R132H) mutation exhibited less IDH-mediated production of NADPH, such that after exposure to ionizing radiation (IR), there were higher levels of reactive oxygen species, DNA double-strand breaks, and cell death compared with IDH1 wild-type cells. These effects were reversed by the IDH1(R132H) inhibitor AGI-5198. Exposure of IDH1 wild-type cells to D-2-hydroxyglutarate was sufficient to reduce IDH-mediated NADPH production and increase IR sensitivity. Mechanistic investigations revealed that the radiosensitivity of heterozygous cells was independent of the well-described DNA hypermethylation phenotype in IDH1-mutated cancers. Thus, our results argue that altered oxidative stress responses are a plausible mechanism to understand the radiosensitivity of IDH1-mutated cancer cells. Further, they offer an explanation for the relatively longer survival of patients with IDH1-mutated tumors, and they imply that administration of IDH1(R132H) inhibitors in these patients may limit irradiation efficacy in this setting.

Mutational profiling of kinases in glioblastoma.

BACKGROUND: Glioblastoma is a highly malignant brain tumor for which no cure is available. To identify new therapeutic targets, we performed a mutation analysis of kinase genes in glioblastoma. METHODS: Database mining and a literature search identified 76 kinases that have been found to be mutated at least twice in multiple cancer types before. Among those we selected 34 kinase genes for mutation analysis. We also included IDH1, IDH2, PTEN, TP53 and NRAS, genes that are known to be mutated at considerable frequencies in glioblastoma. In total, 174 exons of 39 genes in 113 glioblastoma samples from 109 patients and 16 high-grade glioma (HGG) cell lines were sequenced. RESULTS: Our mutation analysis led to the identification of 148 non-synonymous somatic mutations, of which 25 have not been reported before in glioblastoma. Somatic mutations were found in TP53, PTEN, IDH1, PIK3CA, EGFR, BRAF, EPHA3, NRAS, TGFBR2, FLT3 and RPS6KC1. Mapping the mutated genes into known signaling pathways revealed that the large majority of them plays a central role in the PI3K-AKT pathway. CONCLUSIONS: The knowledge that at least 50% of glioblastoma tumors display mutational activation of the PI3K-AKT pathway should offer new opportunities for the rational development of therapeutic approaches for glioblastomas. However, due to the development of resistance mechanisms, kinase inhibition studies targeting the PI3K-AKT pathway for relapsing glioblastoma have mostly failed thus far. Other therapies should be investigated, targeting early events in gliomagenesis that involve both kinases and non-kinases.

The driver and passenger effects of isocitrate dehydrogenase 1 and 2 mutations in oncogenesis and survival prolongation.

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are key events in the development of glioma, acute myeloid leukemia (AML), chondrosarcoma, intrahepatic cholangiocarcinoma (ICC), and angioimmunoblastic T-cell lymphoma. They also cause D-2-hydroxyglutaric aciduria and Ollier and Maffucci syndromes. IDH1/2 mutations are associated with prolonged survival in glioma and in ICC, but not in AML. The reason for this is unknown. In their wild-type forms, IDH1 and IDH2 convert isocitrate and NADP(+) to α-ketoglutarate (αKG) and NADPH. Missense mutations in the active sites of these enzymes induce a neo-enzymatic reaction wherein NADPH reduces αKG to D-2-hydroxyglutarate (D-2HG). The resulting D-2HG accumulation leads to hypoxia-inducible factor 1α degradation, and changes in epigenetics and extracellular matrix homeostasis. Such mutations also imply less NADPH production capacity. Each of these effects could play a role in cancer formation. Here, we provide an overview of the literature and discuss which downstream molecular effects are likely to be the drivers of the oncogenic and survival-prolonging properties of IDH1/2 mutations. We discuss interactions between mutant IDH1/2 inhibitors and conventional therapies. Understanding of the biochemical consequences of IDH1/2 mutations in oncogenesis and survival prolongation will yield valuable information for rational therapy design: it will tell us which oncogenic processes should be blocked and which "survivalogenic" effects should be retained.

Co-occurrence in body site of malformations and cancer.

In many malformation syndromes benign and malignant tumours develop more frequently than in the general population. Malformations result from an abnormal intrinsic developmental process. It can be hypothesised that disturbed regulation of cell growth as can become evident by the presence of benign and malignant tumours, which will occur at the same site of a malformation or at other sites at which the gene involved in the malformation is functioning. The present study aimed to compare the localisation of malignant and benign tumours to the localisation of major and minor characteristics of syndromes that have either of two malformations, i.e. microtia and hypospadias. To eliminate co-occurrence of a malformation syndrome and tumours by chance we confined evaluations to syndromes which have been described in >100 individuals. We identified 11 syndromes associated with microtia and 26 syndromes associated with hypospadias, for which co-localisation of (benign and malignant) tumours with (major and minor) syndrome characteristics was determined. In both groups of syndromes tumours were found to be localised at the same body site as the major and minor characteristics of the syndromes in two-third of the tumours. There was no significant difference in co-occurrence in site between benign and malignant tumours. We conclude that in two groups of malformation syndromes which go along with a different core malformation, benign and malignant tumours co-localise with the core malformation or with other sites at which the gene involved is functioning. This adds further proof that tumours in malformation syndromes can usually be explained by abnormal functioning of the same gene that has caused the malformation syndrome.

Brain tumors and syndromes in children.

(Brain) tumors are usually a disorder of aged individuals. If a brain tumor occurs in a child, there is a possible genetic susceptibility for this. Such genetic susceptibilities often show other signs and symptoms. Therefore, every child with a brain tumor should be carefully evaluated for the presence of a "tumor predisposition syndrome." Here, we provide an overview of the various central nervous system tumors that occur in children with syndromes and of the various syndromes that occur in children with brain tumor. Our aim is to facilitate recognition of syndromes in children with a brain tumor and early diagnosis of brain tumors in children with syndromes. Diagnosing tumor predisposition syndromes in children may have important consequences for prognosis, treatment, and screening for subsequent malignancies and nontumor manifestations. We discuss pitfalls in clinical and molecular diagnoses, and the consequences of diagnosing a hereditary disorder for family members. Our improved knowledge of cancer etiology is increasingly translated into management strategies in syndromes in general and will likely lead in the near future to personalized therapeutic approaches for tumor predisposition syndromes.

The combination of IDH1 mutations and MGMT methylation status predicts survival in glioblastoma better than either IDH1 or MGMT alone.

BACKGROUND: Genetic and epigenetic profiling of glioblastomas has provided a comprehensive list of altered cancer genes of which only O(6)-methylguanine-methyltransferase (MGMT) methylation is used thus far as a predictive marker in a clinical setting. We investigated the prognostic significance of genetic and epigenetic alterations in glioblastoma patients. METHODS: We screened 98 human glioblastoma samples for genetic and epigenetic alterations in 10 genes and chromosomal loci by PCR and multiplex ligation-dependent probe amplification (MLPA). We tested the association between these genetic and epigenetic alterations and glioblastoma patient survival. Subsequently, we developed a 2-gene survival predictor. RESULTS: Multivariate analyses revealed that mutations in isocitrate dehydrogenase 1 (IDH1), promoter methylation of MGMT, irradiation dosage, and Karnofsky Performance Status (KFS) were independent prognostic factors. A 2-gene predictor for glioblastoma survival was generated. Based on the genetic and epigenetic status of IDH1 and MGMT, glioblastoma patients were stratified into 3 clinically different genotypes: glioblastoma patients with IDH1mt/MGMTmet had the longest survival, followed by patients with IDH1mt/MGMTunmet or IDH1wt/MGMTmet, and patients with IDH1wt/MGMTunmet had the shortest survival. This 2-gene predictor was an independent prognostic factor and performed significantly better in predicting survival than either IDH1 mutations or MGMT methylation alone. The predictor was validated in 3 external datasets. DISCUSSION: The combination of IDH1 mutations and MGMT methylation outperforms either IDH1 mutations or MGMT methylation alone in predicting survival of glioblastoma patients. This information will help to increase our understanding of glioblastoma biology, and it may be helpful for baseline comparisons in future clinical trials.

Significance of complete 1p/19q co-deletion, IDH1 mutation and MGMT promoter methylation in gliomas: use with caution.

The histopathological diagnosis of diffuse gliomas often lacks the precision that is needed for tailored treatment of individual patients. Assessment of the molecular aberrations will probably allow more robust and prognostically relevant classification of these tumors. Markers that have gained a lot of interest in this respect are co-deletion of complete chromosome arms 1p and 19q, (hyper)methylation of the MGMT promoter and IDH1 mutations. The aim of this study was to assess the prognostic significance of complete 1p/19q co-deletion, MGMT promoter methylation and IDH1 mutations in patients suffering from diffuse gliomas. The presence of these molecular aberrations was investigated in a series of 561 diffuse astrocytic and oligodendroglial tumors (low grade n=110, anaplastic n=118 and glioblastoma n=333) and correlated with age at diagnosis and overall survival. Complete 1p/19q co-deletion, MGMT promoter methylation and/or IDH1 mutation generally signified a better prognosis for patients with a diffuse glioma including glioblastoma. However, in all 10 patients with a histopathological diagnosis of glioblastoma included in this study complete 1p/19q co-deletion was not associated with improved survival. Furthermore, in glioblastoma patients >50 years of age the favorable prognostic significance of IDH1 mutation and MGMT promoter methylation was absent. In conclusion, molecular diagnostics is a powerful tool to obtain prognostically relevant information for glioma patients. However, for individual patients the molecular information should be interpreted with caution and weighed in the context of parameters such as age and histopathological diagnosis.