Comprehensive analysis of genomic alterations in gliosarcoma and its two tissue components

Primary Intracranial Gliosarcoma: Is It Really a Variant of Glioblastoma? An Update of the Clinical, Radiological, and Biomolecular Characteristics

Gliosarcomas (GS) are sporadic malignant tumors classified as a Glioblastoma (GBM) variant with IDH-wild type phenotype. It appears as a well-circumscribed lesion with a biphasic, glial, and metaplastic mesenchymal component. The current knowledge about GS comes from the limited literature. Furthermore, recent studies describe peculiar characteristics of GS, such as hypothesizing that it could be a clinical-pathological entity different from GBM. Here, we review radiological, biomolecular, and clinical data to describe the peculiar characteristics of PGS, treatment options, and outcomes in light of the most recent literature. A comprehensive literature review of PubMed and Web of Science databases was conducted for articles written in English focused on gliosarcoma until 2023. We include relevant data from a few case series and only a single meta-analysis. Recent evidence describes peculiar characteristics of PGS, suggesting that it might be a specific clinical-pathological entity different from GBM. This review facilitates our understanding of this rare malignant brain tumor. However, in the future we recommend multi-center studies and large-scale metanalyses to clarify the biomolecular pathways of PGS to develop new specific therapeutic protocols, different from conventional GBM therapy in light of the new therapeutic opportunities.

Familial CCM Genes Might Not Be Main Drivers for Pathogenesis of Sporadic CCMs-Genetic Similarity between Cancers and Vascular Malformations

Cerebral cavernous malformations (CCMs) are abnormally dilated intracranial capillaries that form cerebrovascular lesions with a high risk of hemorrhagic stroke. Recently, several somatic "activating" gain-of-function (GOF) point mutations in PIK3CA (phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit p110α) were discovered as a dominant mutation in the lesions of sporadic forms of cerebral cavernous malformation (sCCM), raising the possibility that CCMs, like other types of vascular malformations, fall in the PIK3CA-related overgrowth spectrum (PROS). However, this possibility has been challenged with different interpretations. In this review, we will continue our efforts to expound the phenomenon of the coexistence of gain-of-function (GOF) point mutations in the PIK3CA gene and loss-of-function (LOF) mutations in CCM genes in the CCM lesions of sCCM and try to delineate the relationship between mutagenic events with CCM lesions in a temporospatial manner. Since GOF PIK3CA point mutations have been well studied in reproductive cancers, especially breast cancer as a driver oncogene, we will perform a comparative meta-analysis for GOF PIK3CA point mutations in an attempt to demonstrate the genetic similarities shared by both cancers and vascular anomalies.

Gliosarcoma: The Distinct Genomic Alterations Identified by Comprehensive Analysis of Copy Number Variations

Gliosarcoma (GSM), a histologic variant of glioblastoma (GBM), carries a poor prognosis with less than one year of median survival. Though GSM is similar with GBM in most clinical and pathological symptoms, GBM has unique molecular and histological features. However, as the rarity of GSM samples, the genetic information of this tumor is still lacking. Here, we take a comprehensive analysis of DNA copy number variations (CNV) in GBM and GSM. Whole genome sequencing was performed on 21 cases of GBM and 15 cases of GSM. CNVKIT is used for CNV calling. Our data showed that chromosomes 7, 8, 9, and 10 were the regions where CNV frequently happened in both GBM and GSM. There was a distinct CNV signal in chromosome 2 especially in GSM. The pathway enrichment of genes with CNV was suggested that the GBM and GSM shared the similar mechanism of tumor development. However, the CNV of some screened genes displayed a disparate form between GBM and GSM, such as AMP, BEND2, HDAC6, FOXP3, ZBTB33, TFE3, and VEGFD. It meant that GSM was a distinct subgroup possessing typical biomarkers. The pathways and copy number alterations detected in this study may represent key drivers in gliosarcoma oncogenesis and may provide a starting point toward targeted oncologic analysis with therapeutic potential.

Survival outcomes associated with MGMT promoter methylation and temozolomide in gliosarcoma patients

PURPOSE

Gliosarcoma is an uncommon glioblastoma subtype, for which MGMT promoter methylation's relationship with response to temozolomide chemotherapy is unclear. We therefore examined this question using a national cohort.

METHODS

 The National Cancer Database was queried for patients histopathologically diagnosed with gliosarcoma between 2010 and 2019. The associations between MGMT promoter methylation, first-line single-agent chemotherapy-presumed to be temozolomide herein-and overall survival (OS) were examined using log-rank tests and Cox regression, with correction for multiple testing (p < 0.01 was significant).

RESULTS

580 newly-diagnosed gliosarcoma patients with MGMT status were available, among whom 33.6% were MGMT promoter methylated. Median OS for gliosarcoma patients that received standard-of-care temozolomide and radiotherapy was 12.1 months (99% confidence interval [CI] 10.8-15.1) for MGMT promoter unmethylated and 21.4 months (99% CI 15.4-26.2) for MGMT promoter methylated gliosarcomas (p = 0.003). In multivariable analysis of gliosarcoma patients-which included the potential confounders of age, sex, maximal tumor size, extent of resection, and radiotherapy-receipt of temozolomide was associated with improved OS in both MGMT promoter methylated (hazard ratio [HR] 0.23 vs. no temozolomide, 99% CI 0.11-0.47, p < 0.001) and unmethylated (HR 0.50 vs. no temozolomide, 99% CI 0.29-0.89, p = 0.002) gliosarcomas. MGMT promoter methylation was associated with improved OS among temozolomide-treated gliosarcoma patients (p < 0.001), but not in patients who did not receive chemotherapy (p = 0.35).

CONCLUSION

In a national analysis of gliosarcoma patients, temozolomide was associated with prolonged OS irrespective of MGMT status. These results provide support for the current practice of trimodal therapy for gliosarcoma.

Clinical Correlation and Role of Cyclin D1 Expression in Glioblastoma Patients: A Study From North India

Background/Aims

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor. Cyclin D1 is a protein that in humans is encoded by the CCND1 gene. Cyclin D1 protein is frequently overexpressed in malignant gliomas.

Methods

It is an observational study comprising 40 biopsy-proven cases of GBM in a span of one and half years. Immunohistochemistry (IHC) was used with Cyclin D1 monoclonal antibody. Cyclin D1 on the outcome was assessed using the Kaplan-Meier survival estimate and compared by log-rank test.

Results

Cyclin D1 was expressed in 60% of patients. The majority (72.5%) of patients expired during the study period, out of which 69% showed immune-expression in contrast to living subjects, out of which only 45.5% of patients exhibited expression. The maximum number of glioblastoma patients were aged between 41 and 50 years (40%), followed by those aged between 31 and 40 years (20%). The male to female ratio of study subjects was 3.44:1.

Conclusion

The study concluded that there is no significant association between Cyclin D1 expression status and different demographic, clinical, and outcome variables.

Pediatric Gliosarcoma With and Without Neurofibromatosis Type 1: A Whole-exome Comparison of 2 Patients

Gliosarcoma is rare among pediatric patients and among individuals with Neurofibromatosis Type 1 (NF1). Here we compare 2 pediatric gliosarcoma patients, one of whom has NF1. We performed whole-exome sequencing, methylation, and copy number analysis on tumor and blood for both patients. Whole-exome sequencing showed higher mutational burden in the tumor of the patient without NF1. Copy number analysis showed differences in chromosomal losses/gains between the tumors. Neither tumor showed O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. The NF1 patient survived without progression while the other expired. This is the first reported case of gliosarcoma in a child with NF1.

Genetic alteration and clonal evolution of primary glioblastoma into secondary gliosarcoma

Aims

Secondary gliosarcoma (SGS) rarely arises post treatment of primary glioblastoma multiforme (GBM), and contains gliomatous and sarcomatous components. The origin and clonal evolution of SGS sarcomatous components remain uncharacterized. Therapeutic radiation is mutagenic and can induce sarcomas in patients with other tumor phenotypes, but possible causal relationships between radiotherapy and induction of SGS sarcomatous components remain unexplored. Herein, we investigated the clonal origin of SGS in a patient with primary GBM progressing into SGS post‐radiochemotherapy.

Methods

Somatic mutation profile in GBM and SGS was examined using whole‐genome sequencing and deep‐whole‐exome sequencing. Mutation signatures were characterized to investigate relationships between radiochemotherapy and SGS pathogenesis.

Results

A mutation cluster containing two founding mutations in tumor‐suppressor genes NF1 (variant allele frequency [VAF]: 50.0% in GBM and 51.1% in SGS) and TP53 (VAF: 26.7% in GBM and 50.8% in SGS) was shared in GBM and SGS. SGS exhibited an overpresented C>A (G>T) transversion (oxidative DNA damage signature) but no signature 11 mutations (alkylating‐agents – exposure signature). Since radiation induces DNA lesions by generating reactive oxygen species, the mutations observed in this case of SGS were likely the result of radiotherapy rather than chemotherapy.

Conclusions

Secondary gliosarcoma components likely have a monoclonal origin, and the clone possessing mutations in NF1 and TP53 was likely the founding clone in this case of SGS.

Ependymosarcoma harboring C11orf95:RELA fusion transcript: Report of two cases and review of the literature

Ependymoma is a relatively rare glial tumor of the central nervous system that arise from the cells lining the ventricles and central canal of the spinal cord. Ependymosarcoma (ES) is a newly introduced tumor entity of uncertain prognosis characterized by a rare phenomenon of a malignant mesenchymal transition arising within an ependymoma. ESs are surgically challenging tumors for diagnosis and therapy with a high incidence of morbidity and mortality. Here, we report two diagnostically challenging cases of primary ES in a 25-year-old female and a 17-year-old male. Both the cases presented with progressive and sequential neurological deficits over a period of five to eight months, and histological examination revealed a biphasic gliomesenchymal architecture comprised of anaplastic ependymomatous and sarcomatous components. Molecular genetic analysis revealed the presence of type 1 C11orf95:RELA fusion transcript. To date, 22 cases of ES have been reported in the literature, and only one case harbored type 1 C11orf95:RELA fusion transcript.

Genomic landscape of gliosarcoma: distinguishing features and targetable alterations

Gliosarcoma is an aggressive brain tumor with histologic features of glioblastoma (GBM) and soft tissue sarcoma. Despite its poor prognosis, its rarity has precluded analysis of its underlying biology. We used a multi-center database to characterize the genomic landscape of gliosarcoma. Sequencing data was obtained from 35 gliosarcoma patients from Genomics Evidence Neoplasia Information Exchange (GENIE) 5.0, a database curated by the American Association of Cancer Research (AACR). We analyzed genomic alterations in gliosarcomas and compared them to GBM (n = 1,449) and soft tissue sarcoma (n = 1,042). 30 samples were included (37% female, median age 59 [IQR: 49–64]). Nineteen common genes were identified in gliosarcoma, defined as those altered in > 5% of samples, including TERT Promoter (92%), PTEN (66%), and TP53 (60%). Of the 19 common genes in gliosarcoma, 6 were also common in both GBM and soft tissue sarcoma, 4 in GBM alone, 0 in soft tissue sarcoma alone, and 9 were more distinct to gliosarcoma. Of these, BRAF harbored an OncoKB level 1 designation, indicating its status as a predictive biomarker of response to an FDA-approved drug in certain cancers. EGFR, CDKN2A, NF1, and PTEN harbored level 4 designations in solid tumors, indicating biological evidence of these biomarkers predicting a drug-response. Gliosarcoma contains molecular features that overlap GBM and soft tissue sarcoma, as well as its own distinct genomic signatures. This may play a role in disease classification and inclusion criteria for clinical trials. Gliosarcoma mutations with potential therapeutic indications include BRAF, EGFR, CDKN2A, NF1, and PTEN.

TERT Promoter Alterations in Glioblastoma: A Systematic Review

Simple Summary

Glioblastoma is the most common malignant primary brain tumor in adults. Glioblastoma accounts for 2 to 3 cases per 100,000 persons in North America and Europe. Glioblastoma classification is now based on histopathological and molecular features including isocitrate dehydrogenase (IDH) mutations. At the end of the 2000s, genome-wide sequencing of glioblastoma identified recurrent somatic genetic alterations involved in oncogenesis. Among them, the alterations in the promoter region of the telomerase reverse transcriptase (TERTp) gene are highly recurrent and occur in 70% to 80% of all glioblastomas, including glioblastoma IDH wild type and glioblastoma IDH mutated. This review focuses on recent advances related to physiopathological mechanisms, diagnosis, and clinical implications.

Abstract

Glioblastoma, the most frequent and aggressive primary malignant tumor, often presents with alterations in the telomerase reverse transcriptase promoter. Telomerase is responsible for the maintenance of telomere length to avoid cell death. Telomere lengthening is required for cancer cell survival and has led to the investigation of telomerase activity as a potential mechanism that enables cancer growth. The aim of this systematic review is to provide an overview of the available data concerning TERT alterations and glioblastoma in terms of incidence, physiopathological understanding, and potential therapeutic implications.

Gliosarcoma in patients under 20 years of age. A clinicopathologic study of 11 cases and detailed review of the literature

BACKGROUND

Gliosarcoma is a rare variant of IDH- wild type glioblastoma with both glial and mesenchymal differentiation. It accounts for approximately 2% of glioblastomas and has a poor prognosis similar to that of classic glioblastoma. It is seen mostly between 40 and 60 years of age with a mean age over 50 years. Pediatric gliosarcoma is even rarer than gliosarcoma in adults. We describe the clinicopathological features of gliosarcoma in patients under 20 years of age and determine whether there are significant differences from gliosarcoma in adults. We also present detailed review of published literature on pediatric gliosarcoma.

METHODS

Slides of gliosarcomas in patients under 20 years of age were reviewed. Clinicopathological features were noted in detail and follow up was obtained.

RESULTS

Eleven cases of gliosarcoma were reported in patients under 20 years of age. Ages ranged from three to 19 years (mean age 13 years). Frontal, parietal and temporal lobes were the commonest locations. Mean and median tumor size was six and five cm respectively. All 11 cases demonstrated the classic biphasic pattern. In 10 cases, glial component was astrocytic and was highlighted on GFAP. Sarcomatous component in most cases resembled fibrosarcoma and was high grade in 72.7%. Glial areas were reticulin poor while sarcomatous areas were reticulin rich. In over 45% cases, bizarre tumor giant cells were seen in the sarcomatous areas. In 1 case, sarcomatous areas showed extensive bone and cartilage formation. Other histologic features included hyalinized blood vessels, hemorrhage, infarction, gemistocytic cells, rhabdoid cells etc. Follow up was available in nine patients, five received chemoradiation post resection while three received radiotherapy only. Prognosis was dismal and eight patients died within one to 14 months following resection.

CONCLUSIONS

Gliosarcomas in patients under 20 comprised 13% of all gliosarcomas reported during the study period. Frequency and mean age were higher compared to other published reports. Pathological features were similar to those described in literature. Clinicopathological features and prognosis of pediatric gliosarcomas were similar to adult gliosarcomas.

Hypermutated phenotype in gliosarcoma of the spinal cord

Gliosarcoma is a variant of glioblastoma with equally poor prognosis and characterized by mixed glial and mesenchymal pathology. Metastasis is not uncommon but the involvement of the spinal cord is rare, and comprehensive genetic characterization of spinal gliosarcoma is lacking. We describe a patient initially diagnosed with a low-grade brain glioma via biopsy, followed by adjuvant radiation and temozolomide treatment. Nearly 2 years after diagnosis, she developed neurological deficits from an intradural, extramedullary tumor anterior to the spinal cord at T4, which was resected and diagnosed as gliosarcoma. Whole-exome sequencing (WES) of this tumor revealed a hypermutated phenotype, characterized by somatic mutations in key DNA mismatch repair (MMR) pathway genes, an abundance of C>T transitions within the identified somatic single nucleotide variations, and microsatellite stability, together consistent with temozolomide-mediated hypermutagenesis. This is the first report of a hypermutator phenotype in gliosarcoma, which may represent a novel genomic mechanism of progression from lower grade glioma.

Demographic, radiographic, molecular and clinical characteristics of primary gliosarcoma and differences to glioblastoma

OBJECTIVE

Gliosarcoma (GSC) is a rare histological variant of glioblastoma (GBM). Due to limited evidence regarding clinical, genetic and radiographic characteristics of GSC, this study aimed to analyze independent outcome predictors of GSC, and to address the differences between GSC and GBM concerning the baseline characteristics and patients' survival.

METHODS

Patients treated between 2001 and 2018 for the diagnosis of GBM and GSC were included in this study. Patients' records were reviewed for demographic, clinical, genetic and radiographic characteristics. Univariate, multivariate and propensity score matched analyses were performed.

RESULTS

In the GSC sub-cohort (N = 56), patients' age, preoperative clinical status, midline tumor location and tumor size were found to be independently associated with overall survival. As compared to GBM individuals (N = 1249), a temporal location (p = 0.002), presence of eccentric tumor cysts (p < 0.001), a higher ratio of TP53 staining (p = 0.002) and a lower ratio of GFAP staining (p = 0.005) were characteristic for GSC. The diagnosis of GSC was associated with a poorer survival (p = 0.002) independently of the patients' age, sex, clinical status and extent of resection, However, this association was no more significant, when enhancing the multivariate analysis with molecular-genetic characteristics (IDH1 mutation and MGMT promotor methylation status).

DISCUSSION

Certain radiographic and molecular-genetic patterns present the distinct characteristics of GSC. There is an association between the diagnosis of GSC and a poorer outcome. This difference might be linked to different genetic alterations in GBM and GSC. Prospective studies are needed to further elucidate the characteristics of GSC and develop targeted treatment approaches for this rare variant.

Gliosarcoma with Adenoid and Chondrosarcomatous Differentiation: A Case Report

A heterogeneous group of CNS tumors are characterized by mixed neuroepithelial and mesenchymal features. Glial tumors manifesting this phenomenon are referred to as gliosarcoma. These tumors are usually mistaken for cerebral metastases or meningioma at operation. Their histological studies have revealed an admixture of gliomatous and sarcomatous tissues, which leads to a biphasic pattern. The mesenchymal component can present in different forms such as fibrosarcoma, undifferentiated pleomorphic sarcoma, chondro-osteogenic, and myogenic differentiation, as well as angiosarcomatous and liposarcomatous types. Squamous differentiation, adenoid formations and glandular structures may also be displayed. Herein, we report a rare case who was admitted to the emergency room with decreased consciousness resembling methadone poisoning. Clinical work-up showed a temporoparietal mass on radiological investigation. Histopathological evaluation of the brain mass revealed a gliosarcoma with adenoid formations and a mesenchymal component, which manifested as chondrosarcomatous differentiation. Immunohistochemical studies confirmed the histologic diagnosis through positivity for EMA, GFAP, S100, and vimentin expression in different components.

Evaluating Surgical Resection Extent and Adjuvant Therapy in the Management of Gliosarcoma

Introduction: Gliosarcomas are clinically aggressive tumors, histologically distinct from glioblastoma. Data regarding the impact of extent of resection and post-operative adjuvant therapy on gliosarcoma outcomes are limited.

Methods: Patients with histologically confirmed gliosarcoma diagnosed between 1999 and 2019 were identified. Clinical, molecular, and radiographic data were assembled based on historical records. Comparisons of categorical variables used Pearson's Chi-square and Fisher's exact test while continuous values were compared using the Wilcoxon signed-rank test. Survival comparisons were assessed using Kaplan-Meier statistics and Cox regressions.

Results: Seventy-one gliosarcoma patients were identified. Secondary gliosarcoma was not associated with worse survival when compared to recurrent primary gliosarcoma (median survival 9.8 [3.8 to 21.0] months vs. 7.6 [1.0 to 35.7], p = 0.7493). On multivariable analysis, receipt of temozolomide (HR = 0.02, 95% CI 0.001–0.21) and achievement of gross total resection (GTR; HR = 0.13, 95% CI 0.02–0.77) were independently prognostic for improved progression-free survival (PFS) while only receipt of temozolomide was independently associated with extended overall survival (OS) (HR = 0.03, 95% CI 0.001–0.89). In patients receiving surgical resection followed by radiotherapy and concomitant temozolomide, achievement of GTR was significantly associated with improved PFS (median 32.97 [7.1–79.6] months vs. 5.45 [1.8–26.3], p = 0.0092) and OS (median 56.73 months [7.8–104.5] vs. 14.83 [3.8 to 29.1], p = 0.0252).

Conclusion: Multimodal therapy is associated with improved survival in gliosarcoma. Even in patients receiving aggressive post-operative multimodal management, total surgical removal of macroscopic disease remains important for optimal outcomes.

Gliosarcomas: magnetic resonance imaging findings

BACKGROUND

Central nervous system (CNS) gliosarcoma (GSM) is a rare primary neoplasm characterized by the presence of glial and sarcomatous components.

OBJECTIVE

In this report, we describe the clinical and neuroimaging aspects of three cases of GSM and correlate these aspects with pathological findings. We also provide a brief review of relevant literature.

METHODS

Three patients were evaluated with magnetic resonance imaging (MRI), and biopsies confirmed the diagnosis of primary GSM, without previous radiotherapy.

RESULTS

The analysis of conventional sequences (T1, T1 after contrast injection, T2, Fluid attenuation inversion recovery, SWI and DWI/ADC map) and advanced (proton 1H MR spectroscopy and perfusion) revealed an irregular, necrotic aspect of the lesion, peritumoral edema/infiltration and isointensity of the solid component on a T2-weighted image. These features were associated with irregular and peripheral contrast enhancement, lipid and lactate peaks, increased choline and creatine levels in proton spectroscopy, increased relative cerebral blood volume (rCBV) in perfusion, multifocality and drop metastasis in one of the cases.

CONCLUSION

These findings are discussed in relation to the general characteristics of GSM reported in the literature.

Molecular and clonal evolution in recurrent metastatic gliosarcoma

We discuss the molecular evolution of gliosarcoma, a mesenchymal type of glioblastoma (GBM), using the case of a 37-yr-old woman who developed two recurrences and an extracranial metastasis. She was initially diagnosed with isocitrate dehydrogenase (IDH) wild-type gliosarcoma in the frontal lobe and treated with surgery followed by concurrent radiotherapy with temozolomide. Five months later the tumor recurred in the left frontal lobe, outside the initially resected area, and was treated with further surgery and radiotherapy. Six months later the patient developed a second left frontal recurrence and was again treated with surgery and radiotherapy. Six weeks later, further recurrence was observed in the brain and bone, and biopsy confirmed metastases in the pelvic bones. To understand the clonal relationships between the four tumor instances and the origin of metastasis, we performed whole-genome sequencing of the intracranial tumors and the tumor located in the right iliac bone. We compared their mutational and copy-number profiles and inferred the clonal phylogeny. The tumors harbored shared alterations in GBM driver genes, including mutations in TP53, NF1, and RB1, and CDKN2A deletion. Whole-genome doubling was identified in the first recurrence and the extracranial metastasis. Comparisons of the metastatic to intracranial tumors highlighted a high similarity in molecular profile but contrasting evidence regarding the origin of the metastasis. Subclonal reconstruction suggested a parallel evolution of the recurrent tumors, and that the metastatic tumor was largely derived from the first recurrence. We conclude that metastasis in glioma can be a late event in tumorigenesis.

Clinical Characteristics of Gliosarcoma and Outcomes From Standardized Treatment Relative to Conventional Glioblastoma

Background: Gliosarcoma (GS) is a rare histopathologic variant of glioblastoma (GBM) characterized by a biphasic growth pattern consisting of both glial and sarcomatous components. Reports regarding its relative prognosis compared to conventional GBM are conflicting and although GS is treated as conventional GBM, supporting evidence is lacking. The aim of this study was to characterize demographic trends, clinical outcomes and prognostic variables of GS patients receiving standardized therapy and compare these to conventional GBM. Methods: Six hundred and eighty GBM patients, treated with maximal safe resection followed by radiotherapy with concomitant and adjuvant temozolomide at a single institution, were retrospectively reevaluated by reviewing histopathological records and tumor tissue for identification of GS patients. Clinico-pathological- and tumor growth characteristics were obtained via assessment of medical records and imaging analysis. Kaplan-Meier survival estimates were compared with log-rank testing, while Cox-regression modeling was tested for prognostic factors in GS patients. Results: The cohort included 26 primary gliosarcoma (PGS) patients (3.8%) and 7 secondary gliosarcoma (SGS) patients (1.0%). Compared to conventional GBM tumors, PGS tumors were significantly more often MGMT-unmethylated (73.9%) and located in the temporal lobe (57.7%). GS tumors often presented dural contact, while extracranial metastasis was only found in 1 patient. No significant differences were found between PGS and conventional GBM in progression-free-survival (6.8 and 7.6 months, respectively, p = 0.105) and in overall survival (13.4 and 15.7 months, respectively, p = 0.201). Survival following recurrence was not significantly different between PGS, SGS, and GBM. Temporal tumor location and MGMT status were found associated with PGS survival (p = 0.036 and p = 0.022, respectively). Conclusion: Despite histopathological and location difference between GS and GBM tumors, the patients present similar survival outcome from standardized treatment. These findings support continued practice of radiation and temozolomide for GS patients.

Prognostic factors and clinical outcomes in adult primary gliosarcoma patients: a Surveillance, Epidemiology, and End Results (SEER) analysis from 2004 to 2015

Objective: Gliosarcoma (GSC), a rare malignant brain tumor, is considered as a variant of isocitrate dehydrogenase 1 wild type (IDH1-WT) glioblastoma (GBM). This study aimed to retrospectively analyze the clinical characteristics of GSC and compare whether there are some differences of treatment strategies and outcomes between GSC and GBM patients through Surveillance, Epidemiology, and End Results (SEER) database.Patients and methods: The clinical data of adults diagnosed with primary GSC between 2004 and 2015 were queried from SEER database. The Kaplan-Meier curve and the Cox model were performed to analyze the relationships between clinical parameters and patients' prognosis. Similar analyses were conducted for all primary GBM patients of SEER.Results: In total, 527 GSC and 20,541 GBM patients with complete and valid clinical information were finally enrolled for further analysis. Compared with GBM, GSC owned a proclivity to temporal lobe rather than frontal lobe (p < 0.001), a less conservative extension of resection (EOR) (p < 0.001), and a higher sensitivity to radiotherapy (p < 0.001). As shown by univariate analysis, surgery, radiotherapy and chemotherapy could prolong the overall survival (OS) time of GSC, but EOR did not confer an advantage to the outcomes of patients, no matter whether combined radio/chemotherapy was given. In multivariate analysis, age more than 60 and lack of radio/chemotherapy were identified as independent risk factors for OS of GSC patients.Conclusions: Our study found that although EOR seemed to be important to GBM, the extent of surgery did not show a clear relationship with the improved prognosis of GSC. Additionally, radiotherapy and chemotherapy could prolong patients' survival time significantly, which suggests a more positive role of them in treating GSC and needs further investigations.

Primary Gliosarcoma of the Cerebellum in a Young Pregnant Woman: Management Challenges and Immunohistochemical Features

Background

Gliosarcoma (GS) represents a rare, high-grade (WHO Grade IV), central nervous system neoplasm, characterized by a very poor prognosis. Similar to other high-grade gliomas, GS affects mainly adults in the 5^th-7^th decade of life and presents a higher incidence in males. The most reported locations of GS are the temporal lobe and the frontal lobe, while only eight cases of GS originating from the posterior cranial fossa are reported in the literature.

Case Description

We report the first case occurring during pregnancy in a 33-year-old patient. Diagnosis was obtained on the 15^th week of gestation when patient presented with signs and symptoms of life-threatening raised intracranial pressure. Surgical excision was followed by early recurrence and eventually disease progression because the patient refused adjuvant treatment to save her fetus.

Conclusions

GS should be considered in the differential diagnosis of posterior cranial fossa tumors with radiological features of meningioma or glioblastoma, even in young patients. To this regard, sarcomas, solitary fibrous tumors, and even metastases should be considered, especially in light of the tendency of GS to give rise to extracranial localizations. Whenever an aggressive management with radical excision and adjuvant treatment is not safely achievable, disease progression is likely to be unavoidable.

Gliosarcoma: distinct molecular pathways and genomic alterations identified by DNA copy number/SNP microarray analysis

PURPOSE

Gliosarcoma is a histologic variant of glioblastoma (GBM), and like GBM carries a poor prognosis. Median survival is less than one (1) year with less than 5% of patients alive after 5 years. Although there is no cure, standard treatment includes surgery, radiation and chemotherapy. While very similar to GBM, gliosarcoma exhibits several distinct differences, morphologically and molecularly. Therefore, we report a comprehensive analysis of DNA copy number changes in gliosarcoma using a cytogenomic DNA copy number (CN) microarray (OncoScan®).

METHODS

Cytogenomic DNA copy number microarray (OncoScan®) was performed on 18 cases of gliosarcoma. MetaCore™ enrichment was applied to the array results to detect associated molecular pathways.

RESULTS

The most frequent alteration was copy number loss, comprising 57% of total copy number changes. The number of losses far exceeded the number of amplifications (***, < 0.001) and loss of heterozygosity events (***, < 0.001). Amplifications were infrequent (4.6%), particularly for EGFR. Chromosomes 9 and 10 had the highest number of losses; a large portion of which correlated to CDKN2A/B loss. Copy number gains were the second most common alteration (26.2%), with the majority occurring on chromosome 7. MetaCore™ enrichment detected notable pathways for copy number gains including: HOXA, Rho family of GTPases, and EGFR; copy number loss including: WNT, NF-kß, and CDKN2A; and copy number loss of heterozygosity including: WNT and p53.

CONCLUSIONS

The pathways and copy number alterations detected in this study may represent key drivers in gliosarcoma oncogenesis and may provide a starting point toward targeted oncologic analysis with therapeutic potential.

Evaluating the Association Between the Extent of Resection and Survival in Gliosarcoma

Introduction: Gliosarcoma (GS) is a rare, malignant mixed tumor of the central nervous system with a median survival of approximately 13 months across multiple studies. Although the value of the extent of resection (EOR) has been confirmed as a prognostic survival factor in glioblastoma, no such association has been defined for GS. The goal of this study was to establish an association between EOR and survival and to determine if a threshold of resection exists for which a survival benefit is conferred in GS.

Methods: The authors identified 11 patients with histologically confirmed GS between January 2005 and January 2015, treated at the Hospital of the University of Pennsylvania. Clinical, radiographic, and outcome data were retrospectively reviewed. Volumetric analysis was completed using semi-automated segmentation to measure the change in contrast-enhancing material based on preoperative T1-contrast (T1c) and postoperative T1 & T1c magnetic resonance imaging (MRI) scans. A log-rank test was completed to confirm an association between EOR and survival, and a series of Kaplan-Meier curves were constructed to determine an EOR threshold. Univariate Cox proportional hazards model (CPHM) followed by multivariate CPHM was also completed to evaluate associations between the prognostic clinical and immunohistochemistry variables under consideration.

Results: Extent of resection categories were defined as gross total resection (GTR >95%), subtotal resection (STR 90%-95%), and partial resection (PR <90%). The median overall survival for the groups were as follows: GTR-17.3 months (n=4), STR-12.6 months (n=5), PR-4.3 months (n=2). A statistically significant association (p=05 level) was found between survival and the PR group with the GTR group as reference. Multivariate CPHM confirmed a statistically significant association between increased survival and age, preoperative Karnofsky Performance Status (KPS) scores, postoperative KPS scores, and KI-67 index. Serial Kaplan-Meier curves suggest a survival benefit with an EOR threshold of 94%.

Conclusion: This study agrees with previous correlations in glioblastoma EOR and prolonged survival. For patients undergoing surgical resection for GS, maximal surgical removal, when safely possible, should be attempted as it appears to translate to longer survival times.

Gliosarcoma Is Driven by Alterations in PI3K/Akt, RAS/MAPK Pathways and Characterized by Collagen Gene Expression Signature

Gliosarcoma is a very rare brain tumor reported to be a variant of glioblastoma (GBM), IDH-wildtype. While differences in molecular and histological features between gliosarcoma and GBM were reported, detailed information on the genetic background of this tumor is lacking. We intend to fill in this knowledge gap by the complex analysis of somatic mutations, indels, copy number variations, translocations and gene expression patterns in gliosarcomas. Using next generation sequencing, we determined somatic mutations, copy number variations (CNVs) and translocations in 10 gliosarcomas. Six tumors have been further subjected to RNA sequencing analysis and gene expression patterns have been compared to those of GBMs. We demonstrate that gliosarcoma bears somatic alterations in gene coding for PI3K/Akt (PTEN, PI3K) and RAS/MAPK (NF1, BRAF) signaling pathways that are crucial for tumor growth. Interestingly, the frequency of PTEN alterations in gliosarcomas was much higher than in GBMs. Aberrations of PTEN were the most frequent and occurred in 70% of samples. We identified genes differentially expressed in gliosarcoma compared to GBM (including collagen signature) and confirmed a difference in the protein level by immunohistochemistry. We found several novel translocations (including translocations in the RABGEF1 gene) creating potentially unfavorable combinations. Collected results on genetic alterations and transcriptomic profiles offer new insights into gliosarcoma pathobiology, highlight differences in gliosarcoma and GBM genetic backgrounds and point out to distinct molecular cues for targeted treatment.

Giant parieto-occipital lobe pediatric gliosarcoma: Report of a rare entity and review of literature

Background

Gliosarcoma is a rare high-grade malignant tumor and a variant of glioblastoma characterized by biphasic glial and mesenchymal components. Gliosarcomas occur most commonly in the fifth or sixth decade of life and have a temporal lobe predilection. Occurrence in the pediatric population is extremely rare.

Case Description

Here, we report the case of an 8-year-old child with histologically confirmed gliosarcoma at the parieto-occipital lobe. Only a subtotal resection of the tumor mass could be performed in view of massive bleeding from the tumor bed; and despite postoperative chemotherapy and radiotherapy, the tumor recurred in a short span of time. A repeat surgery was done but the patient could not survive.

Conclusion

To our knowledge, this case constitutes the second youngest case reported in the literature with the lesion in the parieto-occipital region and the third youngest in all pediatric cases of gliosarcoma. This case demonstrates that possibility of gliosarcoma should always be kept in mind in children presenting with features of intracranial high-grade glial tumor. This case also suggests that significant residual after surgery is one variable that may affect the prognosis despite radiotherapy and/or chemotherapy.

Gliosarcoma of Cerebello-Pontine Angle: A Case Report and Review of the Literature

Gliosarcoma (GS), known as variant of glioblastoma multiforme, is aggressive and very rare primary central nervous system malignant neoplasm. They are usually located in the supratentorial area with possible direct dural invasion or only reactive dural thickening. However, in this case, GS was located in lateral side of left posterior cranial fossa. A 78-year-old man was admitted to our hospital with 3 month history of continuous dizziness and gait disturbance without past medical history. A gadolinium-enhanced MRI demonstrated 5.6×4.8×3.2 cm sized mass lesion in left posterior cranial fossa, heterogeneously enhanced. The patient underwent left retrosigmoid craniotomy with navigation system. The tumor was combined with 2 components, whitish firm mass and gray colored soft & suckable mass. On pathologic report, the final diagnosis was GS of WHO grade IV. In spite of successful gross total resection of tumor, we were no longer able to treat because of the patient's rejection of adjuvant treatment. The patient survived for nine months without receiving any special treatment from the hospital.

Clinical and molecular characteristics of gliosarcoma and modern prognostic significance relative to conventional glioblastoma

Gliosarcoma is a rare histopathologic variant of glioblastoma traditionally associated with a poor prognosis. While gliosarcoma may represent a distinct clinical entity given its unique histologic composition and molecular features, its relative prognostic significance remains uncertain. While treatment of gliosarcoma generally encompasses the same standardized approach used in glioblastoma, supporting evidence is limited given its rarity. Here, we characterized 32 cases of gliosarcoma and retrospectively evaluated survival relative to 451 glioblastoma patients diagnosed during the same era within the same institution. Overall, we identified 22 primary gliosarcomas, representing 4.7% of WHO Grade IV primary glioblastomas, and 10 secondary gliosarcomas. With median age of 62, patients were predominately Caucasian (87.5%) and male (65.6%). Tumors with available molecular profiling were primarily MGMT-unmethylated (87.5%), IDH-1-preserved (100%) and EGFR wild-type (100%). Interestingly, while no significant median survival difference between primary gliosarcoma and glioblastoma was observed across the entire cohort (11.0 vs. 14.8 months, p = 0.269), median survival was worse for gliosarcoma specifically among patients who received modern temozolomide-based (TMZ) chemoradiotherapy (11.0 vs. 17.3 months, p = 0.006). Matched-pair analysis also trended toward worse median survival among gliosarcomas (11.0 vs. 19.6 months, log-rank p = 0.177, Breslow p = 0.010). While adjuvant radiotherapy (HR 0.206, p = 0.035) and TMZ-based chemotherapy (HR 0.531, p = 0.000) appeared protective, gliosarcoma emerged as a significantly poor prognostic factor on multivariate analysis (HR 3.27, p = 0.012). Collectively, our results suggest that gliosarcoma may still portend worse prognosis even with modern trimodality therapy.

Detailed magnetic resonance imaging features of a case series of primary gliosarcoma

Objective We aimed to characterise the magnetic resonance imaging (MRI) features of a case series of primary gliosarcoma, with the inclusion of diffusion-weighted imaging and perfusion imaging with dynamic susceptibility contrast MRI. Materials and methods We conducted a retrospective study of cases of primary gliosarcoma from the Pathology Department database from January 2006 to December 2014. Clinical and demographic data were obtained. Two neuroradiologists, blinded to diagnosis, assessed tumour location, signal intensity in T1 and T2-weighted images, pattern of enhancement, diffusion-weighted imaging and dynamic susceptibility contrast MRI studies on preoperative MRI. Results Seventeen patients with primary gliosarcomas had preoperative MRI study: seven men and 10 women, with a mean age of 59 years (range 27-74). All lesions were well demarcated, supratentorial and solitary (frontal n = 5, temporal n = 4, parietal n = 3); 13 tumours abutted the dural surface (8/13 with dural enhancement); T1 and T2-weighted imaging patterns were heterogeneous and the majority of lesions (12/17) showed a rim-like enhancement pattern with focal nodularities/irregular thickness. Restricted diffusion (mean apparent diffusion coefficient values 0.64 × 10^-3 mm²/s) in the more solid/thick components was present in eight out of 11 patients with diffusion-weighted imaging study. Dynamic susceptibility contrast MRI study ( n = 8) consistently showed hyperperfusion in non-necrotic/cystic components on relative cerebral volume maps. Conclusions The main distinguishing features of primary gliosarcoma are supratentorial and peripheral location, well-defined boundaries and a rim-like pattern of enhancement with an irregular thick wall. Diffusion-weighted imaging and relative cerebral volume map analysis paralleled primary gliosarcoma with high-grade gliomas, thus proving helpful in differential diagnosis.

Analysis of Outcomes of Multidisciplinary Management of Gliosarcoma: A Single-Center Study, 2000-2013

BACKGROUND

Gliosarcoma is a rare tumor of the central nervous system with a reported incidence of ∼2%-8% of all gliomas. We reviewed the outcomes of patients treated at our institution over a 14-year period from 2000 to 2013 to characterize overall survival (OS) and progression-free survival as well as to elucidate the additive effect of chemoradiotherapy.

METHODS

From January 1, 2000 to December 31, 2013, we retrospectively reviewed the clinical notes of all patients treated at our institution with a histopathologic diagnosis of gliosarcoma. This review yielded 21 patients whose clinicoradiologic data were analyzed with respect to age, sex, ethnicity, preoperative/postoperative Glasgow Coma Scale and Karnofsky Performance Scale, location, extent of resection, methylguanine DNA methyl transferase methylation status, and administration of adjuvant therapy.

RESULTS

The median age was 58 years (range, 40-80 years) with a male preponderance (1.6:1). Tumor location was mainly temporal (n = 6) but also parietal (n = 5), frontal (n = 4), multilobar (n = 4), and cerebellar (n = 1). Surgical resection was deemed to be total in 15 patients and subtotal in 6 patients. Methylguanine DNA methyl transferase methylation status was available for only 5 patients, with a methylation rate of 60% (3/5) and no impact on survival. Nine patients received both radiotherapy and chemotherapy (OS, 7.9 months), 7 received radiotherapy only (OS, 5.7 months), and 5 patients received no adjuvant therapy (OS, 1.4 months). The overall median survival was 5.7 months (range, 1-21.5 months) and median progression-free survival was 5 months (range, 1.4-12.4 months).

CONCLUSIONS

Despite an overall poor prognosis, a multimodality approach aiming for complete resection followed by radiotherapy and chemotherapy appears to be associated with better outcomes.

High prevalence of TP53 mutations is associated with poor survival and an EMT signature in gliosarcoma patients

Gliosarcoma (GS) is a rare variant (2%) of glioblastoma (GBM) that poses clinical genomic challenges because of its poor prognosis and limited genomic information. To gain a comprehensive view of the genomic alterations in GS and to understand the molecular etiology of GS, we applied whole-exome sequencing analyses for 28 GS cases (6 blood-matched fresh-frozen tissues for the discovery set, 22 formalin-fixed paraffin-embedded tissues for the validation set) and copy-number variation microarrays for 5 blood-matched fresh-frozen tissues. TP53 mutations were more prevalent in the GS cases (20/28, 70%) compared to the GBM cases (29/90, 32%), and the GS patients with TP53 mutations showed a significantly shorter survival (multivariate Cox analysis, hazard ratio=23.9, 95% confidence interval, 2.87-199.63, P=0.003). A pathway analysis showed recurrent alterations in MAPK signaling (EGFR, RASGRF2 and TP53), phosphatidylinositol/calcium signaling (CACNA1s, PLCs and ITPRs) and focal adhesion/tight junction (PTEN and PAK3) pathways. Genomic profiling of the matched recurrent GS cases detected the occurrence of TP53 mutations in two recurrent GS cases, which suggests that TP53 mutations play a role in treatment resistance. Functionally, we found that TP53 mutations are associated with the epithelial-mesenchymal transition (EMT) process of sarcomatous components of GS. We provide the first comprehensive genome-wide genetic alternation profiling of GS, which suggests novel prognostic subgroups in GS patients based on their TP53 mutation status and provides new insight in the pathogenesis and targeted treatment of GS.

Regulation of PI3K effector signalling in cancer by the phosphoinositide phosphatases

Class I phosphoinositide 3-kinase (PI3K) generates phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P₃) at the plasma membrane in response to growth factors, activating a signalling cascade that regulates many cellular functions including cell growth, proliferation, survival, migration and metabolism. The PI3K pathway is commonly dysregulated in human cancer, and drives tumorigenesis by promoting aberrant cell growth and transformation. PtdIns(3,4,5)P₃ facilitates the activation of many pleckstrin homology (PH) domain-containing proteins including the serine/threonine kinase AKT. There are three AKT isoforms that are frequently hyperactivated in cancer through mutation, amplification or dysregulation of upstream regulatory proteins. AKT isoforms have converging and opposing functions in tumorigenesis. PtdIns(3,4,5)P₃ signalling is degraded and terminated by phosphoinositide phosphatases such as phosphatase and tensin homologue (PTEN), proline-rich inositol polyphosphate 5-phosphatase (PIPP) (INPP5J) and inositol polyphosphate 4-phosphatase type II (INPP4B). PtdIns(3,4,5)P₃ is rapidly hydrolysed by PIPP to generate phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P₂), which is further hydrolysed by INPP4B to form phosphatidylinositol 3-phosphate (PtdIns3P). PtdIns(3,4)P₂ and PtdIns3P are also important signalling molecules; PtdIns(3,4)P₂ together with PtdIns(3,4,5)P₃ are required for maximal AKT activation and PtdIns3P activates PI3K-dependent serum and glucocorticoid-regulated kinase (SGK3) signalling. Loss of Pten, Pipp or Inpp4b expression or function promotes tumour growth in murine cancer models through enhanced AKT isoform-specific signalling. INPP4B inhibits PtdIns(3,4)P₂-mediated AKT activation in breast and prostate cancer; however, INPP4B expression is increased in acute myeloid leukaemia (AML), melanoma and colon cancer where it paradoxically promotes cell proliferation, transformation and/or drug resistance. This review will discuss how PTEN, PIPP and INPP4B distinctly regulate PtdIns(3,4,5)P₃ signalling downstream of PI3K and how dysregulation of these phosphatases affects cancer outcomes.

Genetic Alterations in Gliosarcoma and Giant Cell Glioblastoma

The majority of glioblastomas develop rapidly with a short clinical history (primary glioblastoma IDH wild-type), whereas secondary glioblastomas progress from diffuse astrocytoma or anaplastic astrocytoma. IDH mutations are the genetic hallmark of secondary glioblastomas. Gliosarcomas and giant cell glioblastomas are rare histological glioblastoma variants, which usually develop rapidly. We determined the genetic patterns of 36 gliosarcomas and 19 giant cell glioblastomas. IDH1 and IDH2 mutations were absent in all 36 gliosarcomas and in 18 of 19 giant cell glioblastomas analyzed, indicating that they are histological variants of primary glioblastoma. Furthermore, LOH 10q (88%) and TERT promoter mutations (83%) were frequent in gliosarcomas. Copy number profiling using the 450k methylome array in 5 gliosarcomas revealed CDKN2A homozygous deletion (3 cases), trisomy chromosome 7 (2 cases), and monosomy chromosome 10 (2 cases). Giant cell glioblastomas had LOH 10q in 50% and LOH 19q in 42% of cases. ATRX loss was detected immunohistochemically in 19% of giant cell glioblastomas, but absent in 17 gliosarcomas. These and previous results suggest that gliosarcomas are a variant of, and genetically similar to, primary glioblastomas, except for a lack of EGFR amplification, while giant cell glioblastoma occupies a hybrid position between primary and secondary glioblastomas.

An IDH1-mutated primary gliosarcoma: case report

The authors present the case of a primary gliosarcoma with an isocitrate dehydrogenase-1 (IDH1) mutation. A 75-year-old man presented with a 3-day history of multiple focal seizures and was found on MRI to have a 2.2-cm left parietal enhancing mass lesion. Brain MRI for tremor performed 8 years prior to this presentation was normal. En bloc resection revealed a high-grade glioma with sarcomatous components that was immunoreactive for the R132H variant of IDH1 by antibody. Gliosarcoma is a rare variant of glioblastoma that arises most frequently as a primary tumor, and has equal or worse survival and an increased propensity for extracranial metastases compared with other Grade 4 gliomas. In contrast, isocitrate dehydrogenase-1 and -2 mutations are associated with low-grade gliomas with increased survival and less commonly with glioblastoma. To the authors' knowledge, there has been only 1 other published report of a primary gliosarcoma carrying an isocitrate dehydrogenase mutation. This rare genetic-histological combination highlights potential differences between glioblastoma and gliosarcoma and may warrant additional study.

Chemotherapy for intracranial ependymoma in adults

Background

Ependymal tumors in adults are rare, accounting for less than 4 % of primary tumors of the central nervous system in this age group. The low prevalence of intracranial ependymoma in adults limits the ability to perform clinical trials. Therefore, treatment decisions are based on small, mostly retrospective studies and the role of chemotherapy has remained unclear.

Methods

We performed a retrospective study on 17 adult patients diagnosed with intracranial World Health Organisation grade II or III ependymoma, who were treated with chemotherapy at any time during the disease course. Benefit from chemotherapy was estimated by applying Macdonald criteria. Progression-free (PFS) and overall survival (OS) were calculated from start of chemotherapy, using the Kaplan-Meier method.

Results

Eleven patients had supratentorial and 6 infratentorial tumors. Ten patients were treated with temozolomide (TMZ), 3 with procarbazine/lomustine/vincristine (PCV), 3 with platinum-based chemotherapy and 1 patient received epirubicin/ifosfamide. Response rates were as follows: TMZ 8/10 stable disease; PCV 3/3 stable disease; platinum-based chemotherapy 1/3 partial response; epirubicin/ifosfamide 1/1 complete response. PFS rates at 6, 12 and 24 months were 52.9, 35.3 and 23.5 %. OS rates at 6, 12 and 24 months were 82.4, 82.4 and 70.1 %. There was no indication for a favourable prognostic role of O⁶-methylguanyl-DNA-methyltransferase (MGMT) promoter methylation which was detected in 3/12 investigated tumors.

Conclusions

Survival outcomes in response to chemotherapy in adult intracranial ependymoma patients vary substantially, but individual patients may respond to any kind of chemotherapy. There were too few patients to compare survival data between chemotherapeutic subgroups.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2323-0) contains supplementary material, which is available to authorized users.

Evolution of DNA aptamers for malignant brain tumor gliosarcoma cell recognition and clinical tissue imaging

Gliosarcoma, a variant of glioblastoma multiforme (GBM), is a highly invasive malignant tumor. Unfortunately, this disease still marked by poor prognosis regardless of modern treatments. It is of great significance to discover specific molecular probes targeting gliosarcoma for early cancer diagnosis and therapy. Herein, we have selected a group of DNA aptamers with high affinity and selectivity against gliosarcoma cells K308 using cell-SELEX. All the dissociation constants of these aptamers against gliosarcoma cells were in the nanomolar range and aptamer WQY-9 has the highest affinity and good selectivity among them. Furthermore, truncated aptamer sequence, WQY-9-B, shows similar recognition ability to aptamer WQY-9. In addition, WQY-9-B was found to be able to bind selectively and internalize into cytoplasm of target cancer cell at 37 °C. More importantly, compared to a random sequence, aptamer WQY-9-B showed excellent recognition rate (73.3%) for tissue sections of clinical gliosarcoma samples. These data suggests that aptamer WQY-9-B has excellent potential as an effective molecular probe for gliosarcoma diagnosis.

Primary and secondary gliosarcomas: clinical, molecular and survival characteristics

Gliosarcoma is classified by the World Health Organization as a variant of glioblastoma. These tumors exhibit biphasic histologic and immunophenotypic features, reflecting both glial and mesenchymal differentiation. Gliosarcomas can be further classified into primary (de novo) tumors, and secondary gliosarcomas, which are diagnosed at recurrence after a diagnosis of glioblastoma. Using a retrospective review, patients seen at MD Anderson Cancer Center between 2004 and 2014 with a pathology-confirmed diagnosis of gliosarcoma were identified. 34 patients with a diagnosis of gliosarcoma seen at the time of initial diagnosis or at recurrence were identified (24 primary gliosarcomas (PGS), 10 secondary gliosarcomas (SGS)). Molecular analysis performed on fourteen patients revealed a high incidence of TP53 mutations and, rarely, EGFR and IDH mutations. Median overall survival (OS) for all patients was 17.5 months from the diagnosis of gliosarcoma, with a progression free survival (PFS) of 6.4 months. Comparing PGS with SGS, the median OS was 24.7 and 8.95 months, respectively (from the time of sarcomatous transformation in the case of SGS). The median OS in SGS patients from the initial diagnosis of GB was 25 months, with a PFS of 10.7 months. Molecular analysis revealed a higher than expected rate of TP53 mutations in GS patients and, typical of primary glioblastoma, IDH mutations were uncommon. Though our data shows improved outcomes for both PGS and SGS when compared to the literature, this is most likely a reflection of selection bias of patients treated on clinical trials at a quaternary center.

Clinicopathologic implications of NF1 gene alterations in diffuse gliomas

Recent studies have identified somatic alterations in the gene encoding for neurofibromin (NF1) in a subset of glioblastoma (GBM), usually associated with the mesenchymal molecular subtype. To understand the significance of NF1 genetic alterations in diffuse gliomas in general, we evaluated public databases and tested for NF1 copy number alterations in a cohort using fluorescence in situ hybridization. NF1 genetic loss (homozygous NF1 deletions or mutations with predicted functional consequences) was present in 30 (of 281) (11%) GBM and 21 (of 286) (7%) lower-grade gliomas in The Cancer Genome Atlas data. Furthermore, NF1 loss was associated with worse overall and disease-specific survival in the lower-grade glioma, but not GBM, Group in The Cancer Genome Atlas cohort. IDH1 or 2 mutations co-existed in lower-grade gliomas with NF1 loss (36%) but not in GBM. In our cohort studied by fluorescence in situ hybridization, NF1/17q (n = 2) or whole Ch17 (n = 3) losses were only identified in the GBM group (5/86 [6%]). Tumors with NF1/Ch17 loss were predominantly adult GBM (4/5); lacked EGFR amplification (0/4), strong p53 immunolabeling (1/5), or IDH1 (R132H) protein expression (0/5); but expressed the mesenchymal marker podoplanin in 4/5. NF1 genetic loss occurs in a subset of diffuse gliomas, and its significance deserves further exploration.

[Gliosarcoma: rare tumor of the central nervous system--presentation of two cases]

Le gliosarcome est une tumeur primitive mixte du système nerveux central, caractérisée par une prolifération biphasique associant un contingent glial de type glioblastome et un contingent sarcomateux. L’âge moyen de survenue de cette tumeur varie de 40 à 60 ans, avec un sex-ratio homme/femme de 1,8/1. Nous rapportons ici deux cas de gliosarcome traités dans notre service Le traitement standard consiste en une résection chirurgicale de la tumeur suivie d'une radiothérapie externe et parfois d'une chimiothérapie.

C11orf95-RELA fusion present in a primary supratentorial ependymoma and recurrent sarcoma

Ependymomas are rare glial tumors of the central nervous system that arise from the cells lining the ventricles and central canal within the spinal cord. The distribution of these tumors along the neuroaxis varies by age, most commonly involving the spinal cord in adults and the posterior fossa in children. It is becoming evident that ependymomas of infratentorial, supratentorial, and spinal cord location are genetically distinct which may explain the differences in clinical outcomes. A novel oncogenic fusion involving the C11orf95 and RELA genes was recently described in supratentorial ependymomas that results in constitutive aberrant activation of the nuclear factor-kB signaling pathway. Ependymosarcomas are rare neoplasms in which a malignant mesenchymal component arises within an ependymoma. We here describe a case of a sarcoma developing in a patient previously treated with chemotherapy and radiation whose original ependymoma and recurrent sarcoma were both shown to carry the type 1 C11orf95-RELA fusion transcript indicating a monoclonal origin for both tumors.

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo.

The role of key genes and pathways involved in the tumorigenesis of Malignant Mesothelioma

Malignant Mesothelioma (MM) is a very aggressive cancer with low survival rates and often diagnosed at an advanced stage. Several players have been implicated in the development of this cancer, such as asbestos, erionite and the simian virus 40 (SV40). Here, we have reviewed the involvement of erionite, SV40, as well as, the role of several genes (p16(INK4a), p14(ARF), NF2, LATS2, SAV, CTNNB1 and among others), the pathways (RAS, PI3K, Wnt, BCL and Hippo), and their respective roles in the development of MM.

Therapeutic targeting of EGFR-activated metabolic pathways in glioblastoma

INTRODUCTION

The highly divergent histological heterogeneities, aggressive invasion and extremely poor response to treatment make glioblastoma (GBM) one of the most lethal and difficult cancers in humans. Among key elements driving its behavior is epidermal growth factor receptor (EGFR), however, neither traditional therapy including neurosurgery, radiation, temozolomide, nor targeted EGFR therapeutics in clinic has generated promising results to date. Strategies are now focusing on blocking the downstream EGFR-activated metabolic pathways and the key phosphorylated kinases.

AREAS COVERED

Here, we review two major EGFR-activated downstream metabolic pathways including the PI3K/AKT/mTOR and RAS/RAF/MAPK pathways and their key phosphorylated kinase alterations in GBMs. This review also discusses potential pharmacological progress from bench work to clinical trials in order to evaluate specific inhibitors as well as therapeutics targeting PI3K and RAS signaling pathways.

EXPERT OPINION

Several factors impede clinical progress in targeting GBM, including the high rates of acquired resistance, heterogeneity within and across the tumors, complexity of signaling pathways and difficulty in traversing the blood-brain barrier (BBB). Substantial insight into genetic and molecular pathways and strategies to better tap the potential of these agents include rational combinatorial regimens and molecular phenotype-based patient enrichment, each of which will undoubtedly generate new therapeutic approaches to combat these devastating disabilities in the near future.

Diagnostic implications of IDH1-R132H and OLIG2 expression patterns in rare and challenging glioblastoma variants

Recent work has demonstrated that nearly all diffuse gliomas display nuclear immunoreactivity for the bHLH transcription factor OLIG2, and the R132H mutant isocitrate dehydrogenase 1 (IDH1) protein is expressed in the majority of diffuse gliomas other than primary glioblastoma. However, these antibodies have not been widely applied to rarer glioblastoma variants, which can be diagnostically challenging when the astrocytic features are subtle. We therefore surveyed the expression patterns of OLIG2 and IDH1 in 167 non-conventional glioblastomas, including 45 small cell glioblastomas, 45 gliosarcomas, 34 glioblastomas with primitive neuroectodermal tumor-like foci (PNET-like foci), 23 with an oligodendroglial component, 11 granular cell glioblastomas, and 9 giant cell glioblastomas. OLIG2 was strongly expressed in all glioblastomas with oligodendroglial component, 98% of small cell glioblastomas, and all granular cell glioblastomas, the latter being particularly helpful in ruling out macrophage-rich lesions. In 74% of glioblastomas with PNET-like foci, OLIG2 expression was retained in the PNET-like foci, providing a useful distinction from central nervous system PNETs. The glial component of gliosarcomas was OLIG2 positive in 93% of cases, but only 14% retained focal expression in the sarcomatous component; as such this marker would not reliably distinguish these from pure sarcoma in most cases. OLIG2 was expressed in 67% of giant cell glioblastomas. IDH1 was expressed in 55% of glioblastomas with oligodendroglial component, 15% of glioblastomas with PNET-like foci, 7% of gliosarcomas, and none of the small cell, granular cell, or giant cell glioblastomas. This provides further support for the notion that most glioblastomas with oligodendroglial component are secondary, while small cell glioblastomas, granular cell glioblastomas, and giant cell glioblastomas are primary variants. Therefore, in one of the most challenging differential diagnoses, IDH1 positivity could provide strong support for glioblastoma with oligodendroglial component, while essentially excluding small cell glioblastoma.

Genetic and pathologic evolution of early secondary gliosarcoma

Gliosarcoma is a subset of glioblastoma with glial and mesenchymal components. True secondary gliosarcomas (i.e. progressing from lower-grade precursors) in the absence of radiation therapy are very rare. We report the unique case of a 61-year-old male who developed a fibrillary astrocytoma (WHO grade II). In the absence of adjuvant therapy the tumor recurred 3 years later as a gliosarcoma comprising an infiltrating glial component and a curious, early high-grade sarcomatous component surrounding intratumoral vessels. DNA was extracted from formalin fixed paraffin-embedded tissues from the precursor low-grade glioma and from the glioma and sarcomatous components at progression. Samples were hybridized separately to a 300 k Illumina SNP array. IDH1(R132H) mutant protein immunohistochemistry was positive in all tissue components. Alterations identified in all samples included dup(1)(q21q41), del(1)(q41qter), del(2)(q31.1), del(2)(q36.3qter), del(4)(q35.1qter), dup(7)(q22.2q36.3), del(7)(q36.3qter), del(9)(p21.3pter), dup(10)(p13pter), del(10)(q26.13q26.3), dup(17) (q12qter), and copy neutral LOH(20)(p11.23p11.21). The recurrent tumor had additional alterations, including del(3)(p21.31q13.31), del(18)(q21.2qter), and a homozygous del(9)(p21.3)(CDKN2A locus) and the sarcoma component had, in addition, del(4)(p14pter), del(6)(q12qter), del(11)(q24.3qter), and del(16)(p11.2pter). In conclusion, unique copy number alterations were identified during tumor progression from a low-grade glioma to gliosarcoma. A subset of alterations developed specifically in the sarcomatous component.

Amplification of the STOML3, FREM2, and LHFP genes is associated with mesenchymal differentiation in gliosarcoma

Gliosarcoma is a rare glioblastoma variant characterized by a biphasic tissue pattern with alternating areas that display either glial (glial fibrillary acidic protein-positive) or mesenchymal (reticulin-positive) differentiation. Previous analyses have shown identical genetic alterations in glial and mesenchymal tumor areas, suggesting that gliosarcomas are genetically monoclonal, and mesenchymal differentiation was considered to reflect the elevated genomic instability of glioblastomas. In the present study, we compared genome-wide chromosomal imbalances using array comparative genomic hybridization in glial and mesenchymal tumor areas of 13 gliosarcomas. The patterns of gain and loss were similar, except that the gain at 13q13.3-q14.1 (log(2) ratio >3.0), containing the STOML3, FREM2, and LHFP genes, which was restricted to the mesenchymal tumor area of a gliosarcoma. Further analyses of 64 cases of gliosarcoma using quantitative PCR showed amplification of the STOML3, FREM2, and LHFP genes in 14 (22%), 10 (16%), and 7 (11%) mesenchymal tumor areas, respectively, but not in glial tumor areas. Results of IHC analysis confirmed that overexpression of STOML3 and FREM2 was more extensive in mesenchymal than in glial tumor areas. These results suggest that the mesenchymal components in a small fraction of gliosarcomas may be derived from glial cells with additional genetic alterations.

Identification of t(1;19)(q12;p13) and ploidy changes in an ependymosarcoma: a cytogenetic evaluation

Gliosarcoma, a recognized subtype of glioblastoma, is a biphasic tumor exhibiting distinct glial and sarcomatous components. Ependymosarcomas are rarer, biphasic ependymal tumors exhibiting sarcomatous change. Genetic abnormalities associated with this curious phenotype are not well understood. We are presenting the first karyotype of ependymosarcoma with identification of a clonal t(1;19)(q12;p13). Fluorescence in situ hybridization (FISH) was performed with a probe set targeting 1q23 and 19p13.3. Although the tumor did not show evidence of t(1;19)(q23;p13.3) by FISH, increased ploidy was a feature of the sarcomatous component. On clinical follow-up the patient is doing well without evidence of recurrence 55 months after initial resection, and postoperative treatment with irradiation and temozolomide. The significance of the genetic alterations we describe associated with sarcomatoid change in ependymal neoplasms, and ultimately their prognostic relevance, merits further study.

Radiological findings in gliosarcoma. A single institution experience

Gliosarcomas are rare tumors with a poor prognosis composed of intermingled malignant glial and sarcoma elements with an estimated incidence of 1.8-8.0% of all malignant astrocytic neoplasms. We aimed to review the imaging findings in eight patients with gliosarcoma who were treated in our center between 2002 and 2010. The diagnosis was confirmed by morphological and immunohistochemical stains. This study, to the best of our knowledge, is the largest describing the imaging manifestations of this tumor. Although our study revealed no unique radiological features for gliosarcoma, it is important to note that they all demonstrated either dural or ependymal involvement or both. Calcification, hemorrhage or cystic components are described with a tendency for a ring enhancement pattern. Interestingly pre-existing benign looking lesions and associated remotely located small meningiomas are also described.

[Secondary gliosarcoma: case report]

Gliosarcoma is a rare tumor of the central nervous system, consisting of gliomatous and sarcomatous elements. The glioblastoma can undergo a change in phenotype, transforming into a gliosarcoma, especially when the tumor has been treated with radiotherapy. Features unique to gliosarcoma compared to glioblastoma include their potential to appear similar to a meningioma at macroscopy, repeated reports of metastases and infrequency of EGFR mutations. We present a case of secondary gliosarcoma to emphasize on the specificities, essentially diagnostical of this rare entity.

Gliosarcoma arising from a fibrillary astrocytoma

We report a 67-year-old woman who was diagnosed with a gliosarcoma at a second operation after diagnosis of a fibrillary astrocytoma 5 months previously. Initially, she underwent a CT-guided stereotactic biopsy. Histological examination showed fibrillary astrocytoma (World Health Organization [WHO] grade II). Loss of heterozygosity (LOH) on 1p, 10q, and 19q was not detected. She received chemotherapy, but no radiotherapy. Five months after the biopsy, MRI revealed rapid tumor growth. Tissue obtained from partial removal of the tumor revealed gliosarcoma (WHO grade IV), and LOH on 10q and 19q was detected. The history, histopathology, and genetic alterations of this patient are discussed.