RELA Fusion-positive Ependymoma Research Articles

Ependymomas

Ependymal neoplasms are a heterogenous group of neoplasms arising from the progenitors of the cells lining the ventricular system and the spinal central canal. During the last few years, significant novel data concerning oncogenesis, molecular characteristics and clinical correlations of these tumours have been collected, with a strong relevance for their pathological classification. The recently published 5th edition of WHO Classification of Central Nervous System Tumours integrates this novel knowledge and represents a substantial update compared to the previous edition. Concerning supratentorial ependymomas, the previous RELA fusion-positive ependymoma has been renamed into ZFTA fusion-positive and the novel YAP1 fusion-positive ependymoma subtype has been added. Posterior fossa ependymomas should now be allocated either to the Type A or Type B subtypes based on molecular profiling or using the H3 K27me3 immunohistochemical surrogate. Regarding spinal ependymomas, a novel subtype has been added based on a distinctive molecular trait, presence of MYCN amplification, and on the unfavourable outcome. Finally, myxopapillary ependymoma is now classified as a grade 2 tumour in accordance with its overall prognosis which mirrors that of conventional spinal ependymomas. The aim of this review is to present these changes and summarize the current diagnostic framework of ependymal tumours, according to the most recent updates.

DDDR-34. RECURRENT RELA FUSION-POSITIVE EPENDYMOMA TREATED WITH VAL-083 UNDER EXPANDED ACCESS: A CASE REPORT

Abstract Ependymoma is a relatively rare central nervous system tumor accounting for 2-9 % of all neuroepithelial tumors. RELA fusion-positive ependymoma is a subgroup associated with supratentorial location, higher WHO grade and worse prognosis. In addition, there is no standard systemic chemotherapy treatment for adults with recurrent disease. VAL-083 is a bi-functional DNA-targeting agent which rapidly induces inter-strand DNA cross-links at N7-guanine inducing double-strand breaks causing cell death and acts independent of MGMT DNA-repair in high-grade gliomas. We report a 40-year-old male who was initially diagnosed with a right parieto-occipital high-grade glioma, with no somatic mutations including IDH1/2 genes, and with unmethylated MGMT promoter status. He initially underwent gross total resection, followed by chemoradiation with concurrent and adjuvant temozolomide for 12 cycles. Sixteen months later, he developed recurrent disease and had a second resection. Inter- and intragenic fusion analysis of tumor tissue revealed C11orf95-RELA fusion and the diagnosis of RELA fusion-positive ependymoma was established. The patient was not eligible to participate in any clinical trial and received VAL-083 under an expanded access program. He was then treated with VAL-083 (30 mg/m2 for 3 consecutive days every 21 days) and completed 12 cycles during a period of 9 months. No grade 3/4 adverse events such as thrombocytopenia, anemia, neutropenia, or lymphopenia were observed. His liver and renal functions were normal. No dose reduction was required. He also received levetiracetam, alprazolam and prochlorperazine, with no drug interactions. Steroid were not required. He has been under surveillance since completion of systemic treatment with VAL-083 and has remained radiologically stable, with no CSF dissemination, after 12 months. This case highlights that VAL-083 may be a treatment option for recurrent RELA fusion-positive ependymoma refractory to temozolomide-based regimens. Clinicaltrials.gov Identifier: NCT03138629. The treatment plans for this EAP patient were approved by MD Anderson Cancer Center IRB.

Supratentorial extra-axial RELA fusion-positive ependymoma misdiagnosed as meningioma by intraoperative histological and cytological examinations: a case report

BackgroundDura-attached supratentorial extra-axial ependymoma is a very rare type of tumor, with only nine reported cases. Preoperative diagnosis of dura-attached supratentorial extra-axial ependymoma is difficult and often radiologically misdiagnosed as a meningioma. We report a case of dura-attached supratentorial extra-axial ependymoma that was misdiagnosed using intraoperative histological and cytological examinations.Case presentationA 26-year-old Japanese man with headache and nausea was referred to our medical facility. Magnetic resonance imaging revealed a cystic mass of 70 × 53 × 57 mm in the left temporoparietal lobe. A peritumoral band with hyperintensity on T2-weighted imaging was observed at the periphery of the lesion, suggesting an extra-axial lesion with no apparent connection to the ventricle. A dural tail sign was also noted on the gadolinium-enhanced T1-weighted image. Preoperative clinical diagnosis was meningioma. Proliferated tumor cells in sheets with intermingled branching vessels were observed in the frozen tissue. Perivascular rosettes were inconspicuous, and the tumor cells had rhabdoid cytoplasm. The tumor was intraoperatively diagnosed as a meningioma, suspected to be a rhabdoid meningioma. Perivascular rosettes were evident in the formalin-fixed paraffin-embedded tissues, suggesting ependymoma. The tumor cells had eosinophilic cytoplasm without a rhabdoid appearance. Anaplastic features, such as high tumor cellularity, increased mitotic activity, microvascular proliferation, and necrosis, were observed. Ependymal differentiation was confirmed on the basis of ultrastructural analysis. Molecular analysis detected C11orf95-RELA fusion gene. The final diagnosis was RELA fusion-positive ependymoma, World Health Organization grade III.ConclusionOwing to its unusual location, dura-attached supratentorial extra-axial ependymomas are frequently misdiagnosed as meningiomas. Neuropathologists should take great precaution in intraoperatively diagnosing this rare subtype of ependymoma to avoid misdiagnosis of the lesion as other common dura-attached tumors.

TBIO-11. The glutamine transporter and candidate diagnostic and therapeutic target SLC1A5 is associated with subtype-specific metabolic phenotypes and tumor prognosis in pediatric brain cancers

Abstract Glutamine transporters play an important role in supporting increased tumor nutritional demands relative to non-cancerous cells, often through overexpression of the solute carrier (SLC) family of membrane transporters. Preclinical studies in adult cancers demonstrate that targeting glutamine addiction via SLC1A5 inhibition results in growth-inhibitory and tumoricidal effects. Given their relatively higher expression in cancer versus normal brain tissue, SLC transporters represent compelling targets for molecularly-targeted radiation and application of available prognostic amino-acid PET imaging probes. However, the role of SLC transporters in pediatric brain cancers has yet to be investigated. We aimed to understand the relationship of SLC transporter expression with pediatric brain tumor subtypes and their potential prognostic significance using data from the Pediatric Brain Tumor Atlas (PBTA). Using the expression of amino acid transporter genes in ensemble survival models (Reactome: R-HSA-352230), we found that elevated expression of glutamine transporters (SLC1A5, SLC7A5, SLC7A11, SLC38A5, SLC38A3) predicted shorter progression-free survival (PFS) in low-grade gliomas (LGGs) and poorer overall survival in pediatric ependymomas, high-grade gliomas (HGGs), and medulloblastomas. We focused specifically on SLC1A5 given the availability of imaging probes (18 F-Fluoroglutamine and 18F-Fluciclovine) for the corresponding amino acid transporter (ASCT2). Through transcriptome-based consensus clustering, we found that supratentorial, RELA fusion-positive ependymomas and sonic hedgehog-activated medulloblastomas were over-represented among clusters expressing higher levels of SLC1A5 (p = 3.38e-7 and p = 2.18-26, respectively). Kaplan-Meier analysis found that higher expression of SLC1A5 was associated with shorter OS in ependymoma and medulloblastoma (p = 9.8e-4 and p = 0.032) and shorter PFS in LGG (p = 0.022). Gene set analysis showed higher expression and network rewiring of amino acid, lipid, and immune pathways in SLC1A5-high expressing clusters. Our work demonstrates that glutamine transporters, particularly SLC1A5, represent compelling targets in pediatric brain cancers that warrant further investigation for molecularly-targeted treatment and amino-acid PET imaging.

PAX6 is frequently expressed in ependymal tumours and associated with prognostic relevant subgroups

AimsAn ependymoma shows divergent morphological and molecular features depending on their location. The paired box 6 (PAX6) transcription factor is a putative tumour suppressor and drives cancer cells towards a...

RELA fusion-positive ependymoma accompanied by extensive desmoplasia: a case report

We report a case of 33-year-old Japanese male who presented with a headache and visual disturbances. Magnetic resonance imaging revealed a large tumor in the left frontal lobe, measuring 7cm in diameter, which was diagnosed as supratentorial anaplastic ependymoma accompanied by extensive desmoplasia. The patient underwent a gross total resection. Histologically, the tumor cells had oval or short, spindle-shaped nuclei, and proliferating cells in perivascular pseudorosettes with anucleate zones and mitotic figures. Desmoplasia with abundant collagen fibers among the tumor cells was detected at numerous sites, and perinuclear dot- or ring-like immunoreactivity for epithelial membrane antigen was identified. Five years and six months after the initial procedure, a small recurrent tumor was identified at the removal site. The patient underwent a second total resection. The histology of the resected tumor showed decreased collagen production and more apparent anaplastic features as compared to those of the initial tumor. In addition to the histological findings, molecular examinations revealed ependymoma, RELA fusion positive. Although not commonly observed, this case suggests that desmoplasia could be associated with ependymomas, including RELA fusion-positive variant. Moreover, our findings indicate that high-grade ependymoma requires careful, long-term follow-up even if gross total resection is performed.

L1CAM High Expression Associates with Poor Prognosis in Glioma but Does Not Correlate with C11orf95-RELA Fusion.

The latest WHO guideline of CNS tumor defined a RELA fusion-positive ependymoma type with extremely poor prognosis, and the expression of L1CAM was correlated well with the presence of RELA fusion. However, the L1CAM protein expression in large sample gliomas other than ependymoma, its relationship with the RELA gene and its prognostic significance remained unknown. We examined the expression of L1CAM in 565 glioma cases (WHO grade I-IV). The L1CAM IHC-positive cases were selected to test RELA fusion with FISH break-apart probes. L1CAM was positive in 109 cases (19.29%) of all 565 glioma cases, with 18.27% in low-grade gliomas and 19.84% in high-grade gliomas, respectively. Unlike ependymoma, L1CAM protein expression was not correlated with the C11orf95-RELA fusion gene in other gliomas, but it had correction with the patient age (older than 45-year-old, p = 0.006), ATRX mutation (p = 0.003) and Ki67 (p = 0.007). High expression of L1CAM was an independent prognostic factor in our cohort. Further analysis demonstrated that L1CAM strong positive expression was significantly associated with poor prognosis in gliomas, both in our cohort (p < 0.001) and TCGA (p < 0.009) dataset. Although uncorrelated with C11orf95-RELA fusion, L1CAM was a significant poor prognostic marker in glioma patients. More aggressive treatment should be taken for these patients and L1CAM might be a promising therapeutic target in glioma.

In vitro benchmarking of NF-κB inhibitors

Dysregulated activity of the transcription factors of the nuclear factor κb (NF-κB) family has been implicated in numerous cancer types, inflammatory diseases, autoimmune disease, and other disorders. As such, selective NF-κB pathway inhibition is an attractive target to researchers for preclinical and clinical drug development. A plethora of commercially and clinically available inhibitors claim to be NF-κB specific; however, such claims of specificity are rarely quantitative or benchmarked, making the biomedical literature difficult to contextualize. This imprecision is worsened because some NF-κB reporter systems have low signal-to-noise ratios. Herein, we use a robust, defined, commercially available reporter system to benchmark NF-κB agonists and antagonists for the field. We also functionally characterize a RELA fusion-positive ependymoma cell culture with validated NF-κB inhibitor compounds.

PATH-16. HISTOPATHOLOGICAL EPENDYMOMA VARIANTS ARE ASSOCIATED WITH DISTINCT CLINICAL PARAMETERS AND DNA METHYLATION PATTERNS

Abstract According to the current WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas and RELA-fusion positive ependymoma (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e. the clear-cell, papillary, and tanycytic ependymoma. In parallel to this WHO classification scheme, DNA methylation patterns can distinguish nine distinct molecular ependymoma subgroups, some of which tightly overlap with certain histopathological subgroups, e.g. subependyomas or myxopapillary ependymomas. Since very little is known about the molecular background of histological classic ependymoma variants, we analyzed histomorphology, clinical parameters and global DNA methylation patterns of diagnosed tanycytic ependymomas (n=12), clear-cell ependymomas (n=14) and papillary ependymomas (n=19). Surprisingly, up to 42% of these variants did not match to ependymomas using a previously published DNA methylation-based classifier for brain tumors. Among the tumors with a match to one of the nine known ependymoma methylation classes, tanycytic ependymomas were predominantly located in the spine, but showed diverse molecular methylation patterns. Most clear-cell ependymomas showed a common histomorphology, were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas showed a “papillary”, “trabecular” or “pseudo-papillary” growth pattern. Interestingly, a true papillary growth pattern was strongly associated with the molecular class B of posterior fossa ependymoma (PFB), but tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Our results show that the diagnosis of classic histological ependymoma variants can be challenging. While clear-cell and papillary ependymomas harbor common molecular features, tanycytic ependymoma may not represent a molecularly distinct subgroup.

Molecular characterization of histopathological ependymoma variants.

According to the WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas, and RELA-fusion-positive ependymomas (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e., the clear cell, papillary, and tanycytic ependymoma. In parallel, global DNA methylation patterns distinguish nine molecular groups, some of which tightly overlap with histopathological subgroups. However, the match of the aforementioned histological variants to DNA methylation classes remains unclear. We analyzed histomorphology, clinical parameters, and global DNA methylation of tumors with the initial histological diagnoses of tanycytic (n = 12), clear cell (n = 14), or papillary ependymoma (n = 19). Forty percent of these tumors did not match to the epigenetic profile of ependymomas, using a previously published DNA methylation-based classifier for brain tumors. Instead, they were classified as low-grade glioma (n = 3), plexus tumor (n = 2), CNS high-grade neuroepithelial tumor with MN1 alteration (n = 2), papillary tumor of the pineal region (n = 2), neurocytoma (n = 1), or did not match to any known brain tumor methylation class (n = 8). Overall, integrated diagnosis had to be changed in 35.6% of cases as compared to the initial diagnosis. Among the tumors molecularly classified as ependymoma (27/45 cases), tanycytic ependymomas were mostly located in the spine (5/7 cases) and matched to spinal or myxopapillary ependymoma. 6/8 clear cell ependymomas were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas with a positive ependymoma match (12/19 cases) showed either a "papillary" (n = 5), a "trabecular" (n = 1), or a "pseudo-papillary" (n = 6) growth pattern. The papillary growth pattern was strongly associated with the methylation class B of posterior fossa ependymoma (PFB, 5/5 cases) and tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Tumors with pseudo-papillary histology matched to the methylation class of myxopapillary ependymoma (4/6 cases), whereas the trabecular case was anatomically and molecularly a spinal ependymoma. Our results show that the diagnosis of histological ependymoma variants is challenging and epigenetic profiles may improve diagnostic accuracy of these cases. Whereas clear cell and papillary ependymomas display correlations between localization, histology, and methylation, tanycytic ependymoma does not represent a molecularly distinct subgroup.

RELA Fusion in Supratentorial Extraventricular Ependymomas: A Morphologic, Immunohistochemical, and Molecular Study of 43 Cases.

Supratentorial extraventricular ependymomas (STEEs) are relatively rare ependymomas, and their pathologic and genetic characteristics are still poorly understood. The aim of this study was to determine the histologic, immunohistochemical, and RELA fusion features, as well as to clarify in more detail the clinical courses of STEEs. Data from a total of 43 patients with STEEs was analyzed retrospectively. The status of RELA fusion was evaluated using fluorescence in situ hybridization. The expression levels of L1CAM, p65, cyclin D1, and p53 were assessed using immunohistochemistry. Progression-free survival and overall survival were calculated via Kaplan-Meier estimation using the log-rank test. Among all 43 STEEs, 65.1% (28/43) are positive for RELA fusion. Interestingly, almost half of the patients with RELA fusion-positive ependymomas are adults (13/28), and 89.3% (25/28) cases are anaplastic ependymomas, which suggests that RELA fusion testing is necessary in adults with STEEs. We investigated the immunohistochemical status of p65, L1CAM and CCND1 protein expression for their ability to predict RELA fusion status. RELA fusion-positive STEEs are frequently associated with expression of p65 (85.2%), L1CAM (85.2%), and CCND1 (81.5%). The accuracy of predicting RELA fusion status was much higher when the expression of p65 and L1CAM was combined, that is, when both were immunopositive. The status of RELA fusion, p53 overexpression, and extent of tumor resection are significantly associated with prognosis.

DNA methylation-based classification of ependymomas in adulthood: implications for diagnosis and treatment

Ependymal tumors are glial tumors that commonly manifest in children and young adults. Their classification has remained entirely morphological until recently, and surgery and radiotherapy are the main treatment options, especially in adults. Here we sought to correlate DNA methylation profiles with clinical and pathological characteristics in the prospective cohort of the German Glioma Network. Tumors from 122 adult patients with myxopapillary ependymoma, ependymoma, anaplastic ependymoma, subependymoma, or RELA fusion-positive ependymoma classified according to the World Health Organization (WHO) 2016 were subjected to DNA methylation profiling using the Illumina HumanMethylation450 BeadChip platform. Molecular data were correlated with histologic features and clinical characteristics. At a median follow-up of 86.7 months, only 22 patients experienced progression (18.0%) and 13 patients (10.7%) died. Each tumor could be assigned to one of the previously defined molecular ependymoma subgroups. All histologic subependymomas corresponded to subependymoma (SE) DNA methylation subgroups, but the reverse was not true: 19 histologic ependymomas (WHO grade II) were allocated to molecular SE groups. Similarly, all histological myxopapillary ependymomas were assigned to the molecularly defined spinal myxopapillary ependymoma (SP-MPE) class, but this molecular subgroup additionally included 15 WHO grade II ependymomas by histology. Overall, WHO grade II ependymomas distributed into 7 molecular subgroups. Most adult patients with ependymoma show a favorable prognosis. Molecular classification may provide diagnostic and prognostic information beyond histology and facilitate patient stratification in future clinical trials. The prognostic significance of a subependymoma or myxopapillary ependymoma DNA methylation phenotype without corresponding histology requires further study. 1. Ependymoma diagnosed in adult patients most often shows a good prognosis. 2. Molecular classification can support diagnostic and prognostic information beyond histology.

WHO 2016 Classification of gliomas.

Gliomas are the most frequent intrinsic tumours of the central nervous system and encompass two principle subgroups: diffuse gliomas and gliomas showing a more circumscribed growth pattern ('nondiffuse gliomas'). In the revised fourth edition of the WHO Classification of CNS tumours published in 2016, classification of especially diffuse gliomas has fundamentally changed: for the first time, a large subset of these tumours is now defined based on presence/absence of IDH mutation and 1p/19q codeletion. Following this approach, the diagnosis of (anaplastic) oligoastrocytoma can be expected to largely disappear. Furthermore, in the WHO 2016 Classification gliomatosis cerebri is not an entity anymore but is now considered as a growth pattern. The most important changes in the very diverse group of 'nondiffuse' gliomas and neuronal-glial tumours are the introduction of anaplastic pleomorphic xanthoastrocytoma, of diffuse leptomeningeal glioneuronal tumour and of RELA fusion-positive ependymoma as entities. In the last part of this review, after very briefly touching upon classification of neuronal, choroid plexus and pineal region tumours, some practical implications and challenges associated with the WHO 2016 Classification of gliomas are discussed.

Aggressive Supratentorial Ependymoma, RELA Fusion-Positive with Extracranial Metastasis: A Case Report.

Ependymoma is the third most common pediatric primary brain tumor. Ependymomas are categorized according to their locations and genetic abnormalities, and these two parameters are important prognostic factors for patient outcome. For supratentorial (ST) ependymomas, RELA fusion-positive ependymomas show a more aggressive behavior than YAP1 fusion-positive ependymomas. Extracranial metastases of intra-axial neuroepithelial tumors are extremely rare. In this paper, we report a case of aggressive anaplastic ependymoma arising in the right frontoparietal lobe, which had genetically 1q25 gain, CDKN2A homozygous deletion, and L1CAM overexpression. The patient was a 10-year-old boy who underwent four times of tumor removal and seven times of gamma knife surgery. Metastatic loci were scalp and temporalis muscle overlying primary operation site, lung, liver, buttock, bone, and mediastinal lymph nodes. He had the malignancy for 10 years and died. This tumor is a representative case of RELA fusion-positive ST ependymoma, showing aggressive behavior.

A Simplified Overview of World Health Organization Classification Update of Central Nervous System Tumors 2016.

After 8 years, an update of central nervous system (CNS) tumors was published in 2016 after 2007. First time ever, molecular markers along with histology have been used in classification of any tumor. Major changes are seen in glioma and medulloblastoma groups. Few entities have been added such as diffuse midline glioma, H3 K27M-mutant, RELA fusion-positive ependymoma, embryonal tumor with multilayered rosettes, C19MC-altered, and hybrid nerve sheath tumors. Few variants and patterns that no longer have diagnostic and/or biological relevance and have been deleted such as glioblastoma cerebri, protoplasmic and fibrillary astrocytoma, and cellular ependymoma. Other changes include deletion of term “primitive neuroectodermal tumor,” addition of criterion of brain invasion in atypical meningioma, separation of melanotic schwannoma from other schwannoma, and combination of solitary fibrous tumors and hemangiopericytoma as one entity. There is also expansion of entities in nerve sheath tumors and hematopoietic/lymphoid tumors of the CNS. In this review article, we tried to review CNS tumors 2016 classification update in a simplified manner; comparing the differences between 2016 and 2007 CNS tumors classifications with brief description of important molecular markers and finally utility as well as challenges of this classification.

The 2016 WHO Classification of Tumours of the Central Nervous System: The Major Points of Revision.

The updated 2016 edition of the World Health Organization (WHO) Classification of Tumours of the Central Nervous System (CNS) uses molecular parameters and the histology to define the main tumor categories for the first time. This represents a shift from the traditional principle of using neuropathological diagnoses, which are primarily based on the microscopic features, to using molecularly-oriented diagnoses. Major restructuring was made with regard to diffuse gliomas, medulloblastomas and other embryonal tumors. New entities that are defined by both the histological and molecular features include glioblastoma, isocitrate dehydrogenase (IDH)-wildtype and glioblastoma, IDH-mutant; diffuse midline glioma, H3 K27M-mutant; RELA fusion-positive ependymoma; medulloblastoma, wingless (WNT)-activated and medulloblastoma, sonic hedgehog (SHH)-activated; and embryonal tumor with multilayered rosettes, C19MC-altered. In addition, some entities that are no longer diagnostically relevant—such as CNS-primitive neuroectodermal tumor—have been deleted from this updated edition. The WHO2016 certainly facilitates clinical and basic research to improve the diagnosis of brain tumors and patient care.

The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary.

The 2016 World Health Organization Classification of Tumors of the Central Nervous System is both a conceptual and practical advance over its 2007 predecessor. For the first time, the WHO classification of CNS tumors uses molecular parameters in addition to histology to define many tumor entities, thus formulating a concept for how CNS tumor diagnoses should be structured in the molecular era. As such, the 2016 CNS WHO presents major restructuring of the diffuse gliomas, medulloblastomas and other embryonal tumors, and incorporates new entities that are defined by both histology and molecular features, including glioblastoma, IDH-wildtype and glioblastoma, IDH-mutant; diffuse midline glioma, H3 K27M-mutant; RELA fusion-positive ependymoma; medulloblastoma, WNT-activated and medulloblastoma, SHH-activated; and embryonal tumour with multilayered rosettes, C19MC-altered. The 2016 edition has added newly recognized neoplasms, and has deleted some entities, variants and patterns that no longer have diagnostic and/or biological relevance. Other notable changes include the addition of brain invasion as a criterion for atypical meningioma and the introduction of a soft tissue-type grading system for the now combined entity of solitary fibrous tumor / hemangiopericytoma-a departure from the manner by which other CNS tumors are graded. Overall, it is hoped that the 2016 CNS WHO will facilitate clinical, experimental and epidemiological studies that will lead to improvements in the lives of patients with brain tumors.