Alpha-internexin expression predicts outcome in anaplastic oligodendroglial tumors and may positively impact the efficacy of chemotherapy: European organization for research and treatment of cancer trial 26951

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

Background

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

Materials and Methods

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

Results

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

Conclusions

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

The 2016 World Health Organization classification of tumours of the central nervous system

The 2016 WHO classification of tumours of the central nervous system represents the new paradigm among the specialists in the brain tumours and proposes a new approach combining histopathological and molecular features into diagnosis named 'integrated diagnosis'. The aim of this challenge is to overstep the interobserver variability of diagnosis based on previous classifications in order to ensure homogenous biological entities with a more accurate clinical significance. Over the last two decades, several molecular aberrations into gliomagenesis were highlighted and then confirmed as emerging biomarkers through prognostic stratification. In particular, IDH1/IDH2 genes mutations, 1p/19q codeletion and mutations in genes encoding histone H3 variants drastically changed the knowledge about diffuse gliomas inducing the WHO working group to consider the phenotype-genotype approach. In the present review, the historical development of the diagnosis of brain tumours from the 3D spatial configuration to the integration of multidisciplinary data up to recent molecular alterations is discussed. At the national level, the RENOCLIP network (supported by the National Cancer Institute) contributes to improve the standardization of histological diagnosis and the facilitation of access to molecular biology platforms for the detection of genetic aberrations necessary for integrated diagnosis. Importantly, the French POLA cohort allowed to test the clinical impact of the new criteria introduced by 2016 WHO classification of CNS tumours confirming the high accuracy in predicting clinical behaviour for diffuse gliomas.

Loss of expression and prognosis value of alpha-internexin in gastroenteropancreatic neuroendocrine neoplasm

BACKGROUND

The neuronal intermediate filament alpha-internexin (α-internexin) is a cytoskeleton protein which is involved in the tumor initiation and progression. In this study, we examined the expression and prognosis value of α-internexin in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs).

METHODS

α-internexin was detected with immunohistochemical staining in 286 tumor specimens from patients with GEP-NENs. Methylation status of α-internexin was evaluated by bisulfite genomic sequencing. We assessed the prognostic value of α-internexin and its correlation with relevant clinicalpathological characteristics.

RESULTS

The reduced/loss of expression rate of α-internexin in GEP-NEN was 73.4% (210/286), while the positive expression rate was 26.6% (76/286). The difference of α-internexin deficiency was not statistically significant between gastrointestinal NENs (GI-NENs) and pancreatic NENs (pNENs). However, we found significant difference of reduced/loss of α-internexin expression among different sites of GI-NENs (χ² = 43.470, P < 0.001). The reduced/loss of expression of α-internexin was significantly associated with poorly differentiation (P < 0.001) and advanced tumor stage (P < 0.001). Univariate analyses showed that reduced/loss of expression of α-internexin predicted worse overall survival (OS) in GEP-NEN patients (P < 0.001), especially in subtype of GI-NENs (P < 0.001). However, in multivariable regression analysis, α-internexin expression was not an independent prognostic factor. The hypermethylation of α-internexin gene was significantly correlated with protein deficiency in GI-NENs, but not in pNENs. Hypermethylation of several CpG sites was significantly associated with poorly differentiated and advanced stage (P values range from 0.018 to 0.044). However, the methylation status of α-internexin was not associated with patient OS.

CONCLUSIONS

The expression of α-internexin was highly heterougeneous in different sites of GEP-NENs. The reduced/loss of expression of α-internexin was closely related to tumors with aggressiveness and patient's adverse prognosis. The hypermethylation of the regulatory region examined may be an important epigenetic regulation mechanism of α-internexin deficiency in subtype of GI-NENs.

Construction of a specific SVM classifier and identification of molecular markers for lung adenocarcinoma based on lncRNA-miRNA-mRNA network

Background

Novel diagnostic predictors and drug targets are needed for LUAD (lung adenocarcinoma). We aimed to build a specific SVM (support vector machine) classifier for diagnosis of LUAD and identify molecular markers with prognostic value for LUAD.

Methods

The expression differences of miRNAs, lncRNAs and mRNAs between LUAD and normal samples were compared using data from TCGA (The Cancer Genome Atlas) database. A LUAD related miRNA-lncRNA-mRNA network was constructed, based on which feature genes were selected for the construction of LUAD specific SVM classifier. The robustness and transferability of SVM classifier were validated using gene expression profile datasets GSE43458 and GSE10072. Prognostic markers were identified from the network. A set of LUAD-related differentially expressed miRNAs, lncRNAs and miRNAs were identified and a LUAD related miRNA-lncRNA-mRNA network was obtained. The LUAD specific SVM classifier constructed on the basis of the network was robust and efficient for classification of samples from TCGA dataset and two independent validation datasets.

Results

Eight RNAs with prognostic value were identified, including hsa-miR-96, hsa-miR-204, PGM5P2 (phosphoglucomutase 5 pseudogene 2), SFTA1P (surfactant associated 1), RGS20 (regulator of G protein signaling 20), RGS9BP (RGS9-binding protein), FGB (fibrinogen beta chain) and INA (alpha-internexin). Among them, RGS20 and INA were regulated by hsa-miR-96. RGS20 was also regulated by hsa-miR-204, which was a potential target of SFTA1P.

Conclusion

The LUAD specific SVM classifier may serve as a novel diagnostic predictor. hsa-miR-96, hsa-miR-204, PGM5P2, SFTA1P, RGS20, RGS9BP, FGB and INA may serve as prognostic markers in clinical practice.

Impact of 9p deletion and p16, Cyclin D1, and Myc hyperexpression on the outcome of anaplastic oligodendrogliomas

Objective

To study the presence of 9p deletion and p16, cyclin D1 and Myc expression and their respective diagnostic and prognostic interest in oligodendrogliomas.

Methods

We analyzed a retrospective series of 40 consecutive anaplastic oligodendrogliomas (OIII) from a single institution and compared them to a control series of 10 low grade oligodendrogliomas (OII). Automated FISH analysis of chromosome 9p status and immunohistochemistry for p16, cyclin D1 and Myc was performed for all cases and correlated with clinical and histological data, event free survival (EFS) and overall survival (OS).

Results

Chromosome 9p deletion was observed in 55% of OIII (22/40) but not in OII. Deletion was highly correlated to EFS (median = 29 versus 53 months, p<0.0001) and OS (median = 48 versus 83 months, p<0.0001) in both the total cohort and the OIII population. In 9p non-deleted oligodendrogliomas, p16 hyperexpression correlated with a shorter OS (p = 0.02 in OII and p = 0.0001 in OIII) whereas lack of p16 expression was correlated to a shorter EFS and OS in 9p deleted OIII (p = 0.001 and p = 0.0002 respectively). Expression of Cyclin D1 was significantly higher in OIII (median expression 45% versus 14% for OII, p = 0.0006) and was correlated with MIB-1 expression (p<0.0001), vascular proliferation (p = 0.002), tumor necrosis (p = 0.04) and a shorter EFS in the total cohort (p = 0.05). Hyperexpression of Myc was correlated to grade (median expression 27% in OII versus 35% in OIII, p = 0.03), and to a shorter EFS in 9p non-deleted OIII (p = 0.01).

Conclusion

Chromosome 9p deletion identifies a subset of OIII with significantly worse prognosis. The combination of 9p status and p16 expression level identifies two distinct OIII populations with divergent prognosis. Hyperexpression of Bcl1 and Myc appears highly linked to anaplasia but the prognostic value is unclear and should be investigated further.

Contribution of 1p, 19q, 9p and 10q Automated Analysis by FISH to the Diagnosis and Prognosis of Oligodendroglial Tumors According to WHO 2016 Guidelines

Objective

To study the feasibility and the diagnostic and prognostic interest of automated analysis of 1p, 19q, 9p and 10q status by FISH technique in oligodendroglial tumors.

Methods

We analyzed a retrospective series of 33 consecutive gliomas with oligodendroglial histology (originally diagnosed as 24 oligodendrogliomas and 9 oligoastrocytomas). For all cases, automated FISH analysis of 1p, 19q, 9p and 10q status were performed and compared to clinical and histological data, ATRX, IDH1R132H and alpha-internexin status (studied by immunohistochemistry) and overall survival (OS). Manual analysis of 9p and 10q status were also performed and compared to automated analysis to verify the concordance of the two methods.

Results

The 33 gliomas were reclassified into 13 low-grade oligodendrogliomas (OII), 10 anaplastic oligodendrogliomas (OIII), 3 diffuse astrocytomas (AII), 3 anaplastic astrocytomas (AIII) and 4 glioblastomas (GBM) according to the WHO 2016 histological criteria. The 1p and/or 19q imbalanced status were restricted to astrocytomas with no correlation to their grade or their OS. Chromosome 9p deletion was restricted to OIII (70%) and GBM (100%) and was correlated with a shorter OS in the total cohort (p = 0.0007), the oligodendroglioma cohort (p = 0.03) and the astrocytoma cohort (p = 0.001). Concordance between 9p manual and automated analysis was satisfactory (81%, κ = 0.69). Chromosome 10q deletion was restricted to GBMs (50%) and was correlated with a poor OS in both the total cohort (p = 0.003) and the astrocytoma (AS) cohort (p = 0.04). Concordance between manual and automated analysis was satisfactory (79%, κ = 0.62).

Conclusion

Automated analysis of 1p, 19q, 9p and 10q status by FISH is a reliable technique which allows for refined classification of oligodendroglial tumors. 1p and/or 19q imbalanced status is evidence of astrocytic differentiation. 9p deletion is found in high grade oligodendrogliomas and astrocytomas with a poor OS. 10q is related to GBM status and a poor OS.

α-Internexin and Peripherin: Expression, Assembly, Functions, and Roles in Disease

α-Internexin and peripherin are neuronal-specific intermediate filament (IF) proteins. α-Internexin is a type IV IF protein like the neurofilament triplet proteins (NFTPs, which include neurofilament light chain, neurofilament medium chain, and neurofilament high chain) that are generally considered to be the primary components of the neuronal IFs. However, α-internexin is often expressed together with the NFTPs and has been proposed as the fourth subunit of the neurofilaments in the central nervous system. α-Internexin is also expressed earlier in the development than the NFTPs and is a maker for neuronal IF inclusion disease. α-Internexin can self-polymerize in vitro and in transfected cells and it is present in the absence of the NFTP in development and in granule cells in the cerebellum. In contrast, peripherin is a type III IF protein. Like α-internexin, peripherin is specific to the nervous system, but it is expressed predominantly in the peripheral nervous system (PNS). Peripherin can also self-assemble both in vitro and in transfected cells. It is as abundant as the NFTPs in the sciatic nerve and can be considered a fourth subunit of the neurofilaments in the PNS. Peripherin has multiple isoforms that arise from intron retention, cryptic intron receptor site or alternative translation initiation. The functional significance of these isoforms is not clear. Peripherin is a major component found in inclusions of patients with amyotrophic lateral sclerosis (ALS) and peripherin expression is upregulated in ALS patients.

Expression pattern of neuronal intermediate filament α-internexin in anterior pituitary gland and related tumors

PURPOSE

α-Internexin (INA) is a class IV neuronal intermediate filament protein that maintains the morphogenesis of neurons. It is expressed in developing neuroblasts and represents the major component of the cytoskeleton in cerebellar granule cells of adult central nervous system tissue. Data concerning INA expression in the human frontal pituitary lobe and related adenomas (PA) is missing.

METHODS

Using immunohistochemistry we examined the distribution pattern of INA in a large cohort of 152 PA, 11 atypical PA, 4 pituitary carcinomas and 20 normal pituitaries (overall n = 187). Quantity of INA protein expression was semi-quantitatively evaluated and grouped into five categories (0 = 0%; 1 = >0-5%; 2 = >5-35%; 3 = >35-80%; 4 = >80% of cells).

RESULTS

Cellular staining intensity of INA appeared significantly higher in gonadotropinomas (Go, n = 62), null cell adenomas (NC, n = 7) and thyrotropinomas (TSHomas, n = 7) compared to the other tumor subtypes (p ≤ 0.001). Furthermore, Go and NC showed a peculiar pseudorosette-like staining pattern surrounding blood vessels in 85.5% (59/69) of cases. Interestingly, areas exhibiting homogenous INA staining were often associated with oncocytic cell changes and decreased immunohistochemically detectable hormone expression. Only 8.5% (8/94) of other PA showed a comparable INA distribution (p ≤ 0.001).

CONCLUSION

Go, NC as well as TSHomas exhibit high levels of intracellular INA protein indicating neuronal transdifferentiation. A possible impact on pathogenesis and endocrine activity needs further investigation.

Efficacy and patient-reported outcomes with dose-intense temozolomide in patients with newly diagnosed pure and mixed anaplastic oligodendroglioma: a phase II multicenter study

Standard initial therapy for patients with pure and mixed anaplastic oligodendrogliomas (AO/MAO) includes chemotherapy and radiation therapy. Anaplastic oligodendrogliomas with 1p/19q co-deletion are more responsive to chemotherapy. There is concern for potential long-term CNS toxicity of radiation. Hence an approach using chemotherapy initially and reserving radiation for progressive disease is attractive. This multicenter phase II trial included patients with newly diagnosed AO/MAO with central pathology review and 1p/19q assay. Temozolomide was given 150 mg/m(2) days 1-7 and 15-21, every 28 days for 8 cycles. The primary endpoint was progression free survival (PFS). Secondary endpoints included response rate, overall survival (OS), treatment toxicity and health-related quality of life (HRQL). Data from 62 patients enrolled between December 2001 and April 2007 at seven centers were analyzed. Among patients with measurable disease, 8 % achieved complete remission, 56 % had stable disease and 36 % had progression. The median PFS and OS were 27.2 months (95 % CI 11.9-36.3) and 105.8 months (95 % CI 51.5-N/A), respectively. Both 1p loss and 1p/19q co-deletion were positive prognostic factors for PFS (p < 0.001) and OS (p < 0.001); and there was some suggestion that 1p/19q co-deletion also predicted better response to chemotherapy (p = 0.007). Grade 3/4 toxicities were mainly hematological. Significantly improved HRQL in the future uncertainty domain of the brain cancer module was seen after cycle 4 (p < 0.001). This trial achieved outcomes similar to those reported previously. Toxicities from dose-intense temozolomide were manageable. Improvement in at least one HRQL domain increased over time. This trial supports the further study of first-line temozolomide monotherapy as an alternative to radiation therapy for patients with newly diagnosed AO/MAO with 1p 19q co-deleted tumors.

Treatment of large low-grade oligodendroglial tumors with upfront procarbazine, lomustine, and vincristine chemotherapy with long follow-up: a retrospective cohort study with growth kinetics

We treated patients with newly diagnosed and large low-grade oligodendroglial tumors with upfront procarbazine, CCNU and vincristine (PCV) in order to delay radiotherapy. Patients were treated with PCV for a maximum of 6 cycles. The response to treatment was defined according to the RANO criteria; in addition change over time of mean tumor diameters (growth kinetics) was calculated. Thirty-two patients were treated between 1998 and 2006, 18 of which were diagnosed with 1p/19q co-deleted tumors. Median follow-up duration was 8 years (range 0.5-13 years). The median overall survival (mOS) was 120 months and the median progression-free survival (mPFS) was 46 months. Growth kinetics showed an ongoing decrease of the mean tumor diameter after completion of chemotherapy, during a median time of 35 months, but an increase of the mean tumor diameter did not herald progression as detected by RANO criteria. 1p/19q co-deletion was associated with a significant increase in OS (mOS 83 months versus not reached for codeleted tumors; p = 0.003)) and PFS (mPFS 35 months versus 67 months for codeleted tumors; p = 0.024). Patients with combined 1p/19q loss had a 10 year PFS of 34 % and the radiotherapy in these patients was postponed for a median period of more than 6 years. This long-term follow-up study indicates that upfront PCV chemotherapy is associated with long PFS and OS and delays radiotherapy for a considerable period of time in patients with low-grade oligodendroglial tumors, in particular with combined 1p/19q loss.

Oligodendroglial tumors

Oligodendroglial tumors are relatively rare, comprising approximately 5% of all glial neoplasms. Oligodendroglial tumor patients have a better prognosis than those with astrocytic neoplasms, and patients with tumors that contain 1p/19q co-deletions or IDH-1 mutations appear to be particularly sensitive to treatment. In the past decade, scientists have made significant progress in the unraveling the molecular events that relate to the pathogenesis of these neoplasms. There is considerable excitement resulting from the recent reports from two large phase III randomized trials (European Organization for Research and Treatment of Cancer [EORTC] 26951 and Radiation Therapy Oncology Group [RTOG] 9402), which disclosed that patients with newly diagnosed 1p/19q co-deleted anaplastic oligodendroglial tumors have a 7+year increase in median overall survival following chemoradiation, as compared to radiation alone. This has stimulated a renewed interest in the development of new therapeutic strategies for treatment and potential cure of oligodendroglial tumors, based on an improved scientific understanding of the molecular events involved in the pathogenesis of these neoplasms. The goal of this document is to summarize the key translational developments and recent clinical therapeutic trial data, with a correlative perspective on current and future directions.

Predictive biomarkers in adult gliomas: the present and the future

PURPOSE OF REVIEW

This review summarizes recent studies on the predictive value of molecular markers in adult gliomas, including 1p/19q codeletion, MGMT methylation, IDH mutation and markers identified using omics and next-generation sequencing studies.

RECENT FINDINGS

The long-term results of the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer trials in anaplastic oligodendroglial glioma have shown that the 1p/19q codeletion predicts an overall survival benefit from early PCV (procarbazine CCNU vincristine) chemotherapy. This benefit can also be predicted using gene expression-based molecular subtypes of gliomas while the predictive value of the IDH mutation in this context requires further study. In elderly patients with glioblastoma, the analysis of MGMT methylation status in two phase III trials suggests that this alteration may guide treatment decisions; however, this finding still needs confirmation in prospective studies. Omics and next-generation sequencing studies have identified additional potential predictive markers. In particular, IDH mutations, BRAF V600E mutations and FGFR gene fusions might predict efficacy of therapies targeted against these alterations.

SUMMARY

Currently, the 1p/19q codeletion is the only well established predictive marker with clinical utility. However, it is likely that other molecular markers such as MGMT methylation, IDH mutation and those identified using omics and next-generation sequencing studies will further guide treatment decisions in adult gliomas.

Early presentation of primary glioblastoma

BACKGROUND

Clinical and neuroimaging findings of glioblastomas (GBM) at an early stage have rarely been described and those tumors are most probably under-diagnosed. Furthermore, their genetic alterations, to our knowledge, have never been previously reported.

METHODS

We report the clinical as well as neuroimaging findings of four early cases of patients with GBM.

RESULTS

In our series, early stage GBM occurred at a mean age of 57 years. All patients had seizures as their first symptom. In all early stages, MRI showed a hyperintense signal on T2-weighted sequences and an enhancement on GdE-T1WI sequences. A hyperintense signal on diffusion sequences with a low ADC value was also found. These early observed occurrences of GBM developed rapidly and presented the MRI characteristics of classic GBM within a few weeks. The GBM size was multiplied by 32 in one month. Immunohistochemical analysis indicated the de novo nature of these tumors, i.e. absence of mutant IDH1 R132H protein expression, which is a diagnostic marker of low-grade diffuse glioma and secondary GBM.

CONCLUSIONS

A better knowledge of early GBM presentation would allow a more suitable management of the patients and may improve their prognosis.

Adjuvant treatment of anaplastic oligodendrogliomas and oligoastrocytomas

BACKGROUND

Standard care of adjuvant treatment for anaplastic oligodendrogliomas (AO) and anaplastic oligoastrocytomas (AOA) is not yet well defined. The benefit of adjuvant chemotherapy and radiotherapy (RT), given as single modalities or sequentially, is still unclear. Furthermore, insight into the predictive and prognostic impact of various biomarkers is surging.

OBJECTIVES

To compare postoperative sequential RT and chemotherapy to RT alone in adults with newly diagnosed AO or mixed AOA. To evaluate the predictive and prognostic impact of the following biomarkers: codeletion of chromosomes 1p and 19q, O(6)-methylguanine-DNA methyltransferase (MGMT) promotor methylation and isocitrate dehydrogenase (IDH)-1 and -2 mutations.

SEARCH METHODS

We searched the Cochrane Central Register for Controlled Trials (CENTRAL, Issue 1, 2014), MEDLINE (2006 to March week 2, 2014) and EMBASE (2006 to week 11, 2014). We scanned reference lists from relevant studies for any additional articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of adults with AO, AOA or anaplastic astrocytoma (AA) comparing adjuvant treatment of chemotherapy, RT, or sequential chemotherapy and RT. We excluded no specific chemotherapy regimens.

DATA COLLECTION AND ANALYSIS

We critically appraised and extracted data from relevant studies. Based on the differences in participant selection with respect to the definition of AO (two versus three high-risk anaplastic features), the inclusion of AA and sequence of treatment (RT and chemotherapy), we could not consider the results from the three RCTs for meta-analysis.

MAIN RESULTS

Three RCTs, with 931 participants, tested different neoadjuvant treatments: RT alone; sequential RT and procarbazine, lomustine and vincristine (PCV) chemotherapy; PCV chemotherapy alone; and temozolomide chemotherapy alone. None of the studies blinded participants or personnel, and, therefore, are considered at high risk of performance and detection bias. The studies were otherwise at low risk of bias. One study, the European Organisation for Research and Treatment of Cancer (EORTC) trial, demonstrated a statistically significant overall survival (OS) benefit for RT plus PCV, with a median OS of 3.5 years compared with 2.6 years in the RT alone arm (P value = 0.018). This result was reported 10 years after the conclusion of the enrolment, and was not apparent in the original 2008 Cochrane review. Furthermore, with retrospective evaluation of biomarkers, codeletion of complete chromosome arms 1p and 19q and IDH-1 or -2 mutation were independent prognostic factors for OS in two of the RCTs (Radiation Therapy Oncology Group (RTOG) and EORTC), and were predictive for OS in one trial (RTOG). The third trial (NOA-04) evaluated these biomarkers prospectively and found them prognostic for progression-free survival.

AUTHORS' CONCLUSIONS

Early PCV, either before or after RT, appears to improve OS of participants with AO or AOA. Use of biomarkers including codeletion of chromosomes 1p and 19q with or without IDH-1 or -2 mutation identify a subset of people with increased sensitivity to combined PCV and RT. The important role of biomarkers was supported in all of the RCTs examined, and prospective evaluation should be undertaken in future studies. However, PCV was associated with significant grade 3 and 4 toxicities, and whether temozolomide can be substituted for this remains unclear.

Mitotic index, microvascular proliferation, and necrosis define 3 groups of 1p/19q codeleted anaplastic oligodendrogliomas associated with different genomic alterations

BACKGROUND

The aim of this study was to correlate histological features and molecular characteristics in anaplastic oligodendrogliomas (AOs).

METHODS

The histological characteristics of 203 AO patients, enrolled in the French national network POLA, were analyzed. The genomic profiles of 191 cases were studied using genomic arrays. IDH mutational status was assessed by immunohistochemistry and direct sequencing.

RESULTS

1p/19q codeletion was present in 79% of cases and was associated with alpha-internexin expression (P < 10(-4)), IDH1/2 mutation (P < 10(-4)), chromosome 4 loss (P < 10(-3)), and better overall survival (P < 10(-4)). Based on mitotic index, microvascular proliferation (MVP), and necrosis, 3 groups of 1p/19q codeleted AOs were identified: (group 1) AO with more than 5 mitoses per 10-HPF, no MVP, and no necrosis; (group 2) AO with MVP and no necrosis; and (group 3) AO with MVP and necrosis. Compared with group 1, groups 2 and 3 AOs had a higher mean Ki-67 proliferation index and a higher rate of 9p and 9q losses. Compared with group 2, group 3 AOs had a higher number of chromosomal alterations including chromosome 4 loss. In the subgroup of 157 1p/19q codeleted AOs, chromosomal instability was associated with shorter progression-free survival (P = .024) and shorter overall survival (P = .023).

CONCLUSIONS

The present study shows that oligodendrogliomas with classic histological features remain a molecularly heterogeneous entity and should be stratified according to 1p/19q status because of its major prognostic relevance. Moreover, 1p/19q codeleted AOs are also heterogeneous. Interestingly, mitotic index, MVP, and necrosis help to classify them into 3 groups associated with distinct genomic alterations.

Molecular analysis of diffuse intrinsic brainstem gliomas in adults

Diffuse intrinsic brainstem gliomas (DIBG) account for 1-2 % of adult gliomas. Their biological characteristics are scarcely understood and whether DIBG are biologically different from supratentorial gliomas remains to be established. We analyzed 17 DIBG samples for IDH1 R132H, alpha internexin, p53, and Ki67 expression, and, in a subset with sufficient DNA amount, for IDH1 and histone H3 mutational status, genomic profiling and MGMT promoter methylation status. A series of 738 adult supratentorial gliomas was used for comparison. Median age at diagnosis was 41 years (range 18.9-65.3 years). Median overall survival was 48.7 months (57 months for low-grade vs. 16 months for high-grade gliomas, p < 0.01). IDH1 sequencing revealed two mutations (IDH1 (R132G) , IDH1 (R132C) ) out of 7 DIBG whereas the R132H IDH1 enzyme was detected in 1/17 DIBG, suggesting that IDH1 mutations are mostly non R132H in DIBG (2/2), in contrast to supratentorial gliomas (31/313; p = 0.01). Mutations in histone genes H3F3A (encoding H3.3) and HIST1H3B (encoding H3.1) were found in 3/8 (37.5 %) of the DIBG (two H3F3A (K27M) and one HIST1H3B (K27M) ) versus 6/205 (2.9 %) of the supratentorial high-grade gliomas (four H3F3A (G34R) and two H3F3A (K27M) ) (p = 0.002). The CGH array showed a higher frequency of chromosome arm 1q gain, 9q gain and 11q loss in DIBG compared to the supratentorial high-grade gliomas, which had a less frequent chromosome 7 gain, and a less frequent chromosome 10 loss. No EGFR amplification was found. These data suggest that adult DIBG differ from adult supratentorial gliomas. In particular, histone genes (H3F3A (K27M) , HIST1H3B (K27M) ) mutations are frequent in adult DIBG whereas IDH1 (R132H) mutations are rare.

MGMT-STP27 methylation status as predictive marker for response to PCV in anaplastic Oligodendrogliomas and Oligoastrocytomas. A report from EORTC study 26951

PURPOSE

The long-term follow-up results from the EORTC-26951 trial showed that the addition of procarbazine, CCNU, and vincristine (PCV) after radiotherapy increases survival in anaplastic oligodendrogliomas/oligoastrocytomas (AOD/AOA). However, some patients appeared to benefit more from PCV treatment than others.

EXPERIMENTAL DESIGN

We conducted genome-wide methylation profiling of 115 samples included in the EORTC-26951 trial and extracted the CpG island hypermethylated phenotype (CIMP) and MGMT promoter methylation (MGMT-STP27) status.

RESULTS

We first show that methylation profiling can be conducted on archival tissues with a performance that is similar to snap-frozen tissue samples. We then conducted methylation profiling on EORTC-26951 clinical trial samples. Univariate analysis indicated that CIMP+ or MGMT-STP27 methylated tumors had an improved survival compared with CIMP- and/or MGMT-STP27 unmethylated tumors [median overall survival (OS), 1.05 vs. 6.46 years and 1.06 vs. 3.8 years, both P < 0.0001 for CIMP and MGMT-STP27 status, respectively]. Multivariable analysis indicates that CIMP and MGMT-STP27 are significant prognostic factors for survival in presence of age, sex, performance score, and review diagnosis in the model. CIMP+ and MGMT-STP27 methylated tumors showed a clear benefit from adjuvant PCV chemotherapy: the median OS of CIMP+ samples in the RT and RT-PCV arms was 3.27 and 9.51 years, respectively (P = 0.0033); for MGMT-STP27 methylated samples, it was 1.98 and 8.65 years. There was no such benefit for CIMP- or for MGMT-STP27 unmethylated tumors. MGMT-STP27 status remained significant in an interaction test (P = 0.003). Statistical analysis of microarray (SAM) identified 259 novel CpGs associated with treatment response.

CONCLUSIONS

MGMT-STP27 may be used to guide treatment decisions in this tumor type.

Combining two biomarkers, IDH1/2 mutations and 1p/19q codeletion, to stratify anaplastic oligodendroglioma in three groups: a single-center experience

IDH1/2 mutations and 1p/19q codeletion occur frequently in anaplastic gliomas and are prognostic factors. We combined these two biomarkers to stratify patients treated for anaplastic oligodendroglioma (AO). 43 consecutive WHO AO were selected. We combined immunohistochemistry (IHC) with the monoclonal antibody mIDH1R132H and DNA sequencing of IDH1 and IDH2 genes. Fluorescence in situ hybridization was carried out to evaluate 1p/19q codeletion. These biomarkers were correlated with progression-free survival (PFS) and overall survival (OS). IDH1/IDH2 mutations occurred in 23/43 (54 %) patients: 20/43 IDH1-R132H mutation in IHC, 2/43 IDH1-R132G mutation and 1/43 IDH2-R172K mutation identified by DNA sequencing. 1p/19q codeletion was detected for 23/43 patients. With median follow-up of 19 months (range 1.4-128), median PFS and OS were 22 and 35 months respectively. IDH1/IDH2 mutations were strongly associated with improved PFS and OS: 5-year PFS was 86 versus 6 % and 5-year OS was 91 versus 9 % for patients with IDH1/IDH2 mutations versus wild-type IDH respectively. In multivariate analyses, IDH1/IDH2 mutations and 1p/19q loss were independent prognostic factors. Three groups with distinct prognostic features were identified: patients with IDH1/2 mutations and 1p/19q loss (median PFS, median OS not reached), patients with IDH1/2 mutations or 1p/19q loss (median PFS: 22 months, median OS: 30 months), and patients without IDH1/2 mutations nor 1p/19q loss with a bad prognosis (median PFS: 8.6 months, median OS: 9.9 months). Combining two biomarkers, IDH1/2 and 1p/19q codeletion, makes it possible to stratify AO in three groups with very distinct prognostic features.

[Guidelines for adult diffuse gliomas WHO grade II, III and IV: pathology and biology. Société franc¸aise de neuropathologie . Réseau de neuro-oncologie pathologique]

Pathological diagnosis plays a major role in the therapeutic management of adult diffuse gliomas. It is based on the histopathological analysis of a representative specimen. Therefore pathologists might be aware of the neuroradiological features of the lesions. Pathologists play a major role in the management of biological resources. Pathologists should classify adult gliomas according to WHO 2007 classification (histological subtype and grade). In addition, in order to provide the histomolecular classification of adult gliomas, search for molecular markers of diagnostic, prognostic or predictive of therapeutic responses must be performed by appropriate and validated immunohistochemical and molecular techniques. In all diffuse gliomas, whatever their grade, search for IDH1 R132H and P53 expression is required. Search for IDH1 minor mutations and IDH2 mutations is required in grade II and III IDH1 R132H negative gliomas whereas 1p19q codeletion should be searched for in grade II and III gliomas with an oligodendroglial component. Search for EGFR amplification and MGMT promoter methylation is recommended. It is strongly recommended to fill the standardized form for pathology and molecular features (validated by the French Society of Neuropathology) in all adult diffuse gliomas.

IDH mutations in human glioma

A novel mutation of isocitrate dehydrogenase-1 (IDH1) was recently found in a large percentage of secondary human gliomas. Unlike previously discovered prognostic molecular characteristics, IDH1 mutations were found across gliomas of many different grades and histologies. Further studies have illuminated its utility as a prognostic marker in low-grade and high-grade gliomas and its ability to aid the differentiation and diagnosis of various tumors with histologic ambiguity. As a metabolic enzyme, its inhibitory actions and neomorphic activity present a unique avenue in the understanding of these tumors and potentially a novel mechanism through which they may be treated.

Immunohistochemical detection of IDH1 mutation, p53, and internexin as prognostic factors of glial tumors

Isocitrate dehydrogenase 1 (IDH1) mutations, which are early and frequent genetic alterations in astrocytomas, oligodendrogliomas, oligoastrocytomas, and secondary glioblastomas, are specific to arginine 132 (R132). Recently, we established monoclonal antibodies (mAbs) against IDH1 mutations: anti-IDH1-R132H and anti-IDH1-R132S. However, the importance of immunohistochemistry using the combination of those mAbs has not been elucidated. For this study, 164 cases of glioma were evaluated immunohistochemically for IDH1 mutations (R132H and R132S) using anti-IDH1 mAbs (HMab-1 and SMab-1). IDH1 mutation was detected, respectively, in 9.7%, 63.6%, 51.7%, and 77.8% of primary grade IV, secondary grade IV, grade III, and grade II gliomas. For each grade of glioma, prognostic factors for progression-free survival and overall survival were evaluated using clinical and pathological parameters in addition to IDH1 immunohistochemistry. IDH1 mutation, p53 overexpression, and internexin expression, as evaluated using immunohistochemistry with clinical parameters such as degree of surgical removal and preoperative Karnofsky Performance Status (KPS), might be of greater prognostic significance than histological grading alone in grade III as well as IDH1 mutation in grade IV gliomas.

[Pathological aspects of the tumors of the lateral ventricles]

Typing a tumor of the lateral ventricle is often an issue, even for an experienced Neuropathologist. In this location are encountered specific entities, such as neurocytoma and subependymal giant cell astrocytoma, as well as more usual tumors, displaying a common misleading morphology, for instance a main clear cell component. The panel of diagnostic tools given to the pathologists has been increasing for a few years, enriched by immunohistochemical and molecular probes.

The clinical implications and biologic relevance of neurofilament expression in gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

Although gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) exhibit widely divergent behavior, limited biologic information (apart from Ki-67) is available to characterize malignancy. Therefore, the identification of alternative biomarkers is a key unmet need. Given the role of internexin alpha (INA) in neuronal development, the authors assessed its function in neuroendocrine cell systems and the clinical implications of its expression as a GEP-NEN biomarker.

METHODS

Functional assays were undertaken to investigate the mechanistic role of INA in the pancreatic BON cell line. Expression levels of INA were investigated in 50 pancreatic NENs (43 primaries, 7 metastases), 43 small intestinal NENs (25 primaries, 18 metastases), normal pancreas (n = 10), small intestinal mucosa (n = 16), normal enterochromaffin (EC) cells (n = 9), mouse xenografts (n = 4) and NEN cell lines (n = 6) using quantitative polymerase chain reaction, Western blot, and immunostaining analyses.

RESULTS

In BON cells, decreased levels of INA messenger RNA and protein were associated with the inhibition of both proliferation and mitogen-activated protein kinase (MAPK) signaling. INA was not expressed in normal neuroendocrine cells but was overexpressed (from 2-fold to 42-fold) in NEN cell lines and murine xenografts. In pancreatic NENs, INA was overexpressed compared with pancreatic adenocarcinomas and normal pancreas (27-fold [P = .0001], and 9-fold [P = .02], respectively). INA transcripts were correlated positively with Ki-67 (correlation coefficient [r] = 0.5; P < .0001) and chromogranin A (r = 0.59; P < .0001). INA distinguished between primary tumors and metastases (P = .02), and its expression was correlated with tumor size, infiltration, and grade (P < .05).

CONCLUSIONS

INA is a novel NEN biomarker, and its expression was associated with MAPK signaling and proliferation. In clinical samples, elevated INA was correlated with Ki-67 and identified malignancy. INA may provide additional biologic information relevant to delineation of both pancreatic NEN tumor phenotypes and clinical behavior.

Histomolecular classification of adult diffuse gliomas: the diagnostic value of immunohistochemical markers

Adult gliomas are most often infiltrative. The World Health Organization (WHO) has classed them into three major groups according to the presomptive cell of origin: astrocytoma, oligodendroglioma and mixed oligoastrocytoma. Depending on the presence or absence of a small number of signs of anaplasia (mitosis, nuclear atypia, cell density, microvascular proliferation and necrosis) the WHO distinguishes grade II (LGG), III (anaplastic), and IV (glioblastomas, GBM). Mutation in the isocitrate deshydrogenase I and II (IDH1 and 2) genes distinguishes grade II, III and secondary GBM from primary GBM. Moreover two additional genetic alterations are recorded in grade II and III gliomas: TP53 mutations that characterize astrocytomas and 1p19q codeletion (as the result of t(1;19)(q10;p10) translocation) recorded in oligodendrogliomas. Mixed gliomas, the most non-reproducible category, share with astrocytomas and oligodendrogliomas the same genetic alterations. Interestingly TP53 mutation (p53+) and 1p19q codeletion (1p19q+) are mutually exclusive and involve IDH mutated (IDH+) glial precursor cells. According to IDH, TP53, and 1p19q status, four major subtypes of LGG are recorded: IDH+/p53-/1p19q-, IDH+/p53+/1p19q-, IDH+/p53-/1p19q+ and triple negative, this last subgroup having the worst prognosis. Interestingly, p53 expression and internexin alpha (INA) expression can replace to some extent TP53 mutation and 1p19 codeletion, respectively. Moreover the antibody directed against the IDH1R132H isoform is highly specific. Because this mutation is the most frequent it is sufficient to assess IDH status in more than 80% of grade II and III gliomas. Taken together these three immunohistochemical markers are contribute greatly to the classification of gliomas and should be tested routinely as diagnostic markers. Finally, although GBM are genetically heterogeneous, the vast majority display EGFR amplification, often associated with EGFR expression, which can be helpful for diagnosis in certain cases.