The role of telomerase reverse transcriptase (TERT) in gliomagenesis has been recently further strengthened by the frequent occurrence of TERT promoter mutations (TERTp-mut) in gliomas and evidence ...that the TERT SNP genetic rs2736100 influences glioma risk. TERTp-mut creates a binding site for Ets/TCF transcription factors, whereas the common rs2853669 polymorphism disrupts another Ets/TCF site on TERT promoter.
We sequenced for TERTp-mut in 807 glioma DNAs and in 235 blood DNAs and analysed TERT expression by RT-PCR in 151 samples. TERTp-mut status and TERTp polymorphism rs2853669 were correlated with histology, genomic profile, TERT mRNA expression, clinical outcome and rs2736100 genotype.
TERTp-mut identified in 60.8% of gliomas (491 out of 807) was globally associated with poorer outcome (Hazard ratio (HR)=1.50). We defined, based on TERTp-mut and IDH mutation status, four prognostic groups: (1) TERTp-mut and IDH-mut associated with 1p19q codeletion, overall survival (OS)>17 years; (2) TERTp-wt and IDH-mut, associated with TP53 mutation, OS=97.5 months; (3) TERTp-wt and IDH-wt, with no specific association, OS=31.6 months; (4) TERTp-mut and IDH-wt, associated with EGFR amplification, OS=15.4 months. TERTp-mut was associated with higher TERT mRNA expression, whereas the rs2853669 variant was associated with lower TERT mRNA expression. The mutation of CIC (a repressor of ETV1-5 belonging to the Ets/TCF family) was also associated with TERT mRNA upregulation.
In addition to IDH mutation status, defining the TERTp-mut status of glial tumours should afford enhanced prognostic stratification of patients with glioma. We also show that TERTp-mut, rs2853669 variant and CIC mutation influence Tert expression. This effect could be mediated by Ets/TCF transcription factors.
Oncogenic fusions consisting of fibroblast growth factor receptor (FGFR) and TACC are present in a subgroup of glioblastoma (GBM) and other human cancers and have been proposed as new therapeutic ...targets. We analyzed frequency and molecular features of FGFR-TACC fusions and explored the therapeutic efficacy of inhibiting FGFR kinase in GBM and grade II and III glioma.
Overall, 795 gliomas (584 GBM, 85 grades II and III with wild-type and 126 with IDH1/2 mutation) were screened for FGFR-TACC breakpoints and associated molecular profile. We also analyzed expression of the FGFR3 and TACC3 components of the fusions. The effects of the specific FGFR inhibitor JNJ-42756493 for FGFR3-TACC3-positive glioma were determined in preclinical experiments. Two patients with advanced FGFR3-TACC3-positive GBM received JNJ-42756493 and were assessed for therapeutic response.
Three of 85 IDH1/2 wild-type (3.5%) but none of 126 IDH1/2-mutant grade II and III gliomas harbored FGFR3-TACC3 fusions. FGFR-TACC rearrangements were present in 17 of 584 GBM (2.9%). FGFR3-TACC3 fusions were associated with strong and homogeneous FGFR3 immunostaining. They are mutually exclusive with IDH1/2 mutations and EGFR amplification, whereas they co-occur with CDK4 amplification. JNJ-42756493 inhibited growth of glioma cells harboring FGFR3-TACC3 in vitro and in vivo. The two patients with FGFR3-TACC3 rearrangements who received JNJ-42756493 manifested clinical improvement with stable disease and minor response, respectively.
RT-PCR sequencing is a sensitive and specific method to identify FGFR-TACC-positive patients. FGFR3-TACC3 fusions are associated with uniform intratumor expression of the fusion protein. The clinical response observed in the FGFR3-TACC3-positive patients treated with an FGFR inhibitor supports clinical studies of FGFR inhibition in FGFR-TACC-positive patients.
BACKGROUND: The importance of telomerase reverse transcriptase (TERT) in gliomagenesis has been recently strengthened by the frequent occurrence of TERT promoter mutations in glioblastomas. METHODS: ...We sequenced the TERT promoter mutation in DNA from 395 glioblastomas and analyzed the results with their respective histology, genetic profile (IDH1 mutation, EGFR amplification, CDKN2A homozygous deletion, loss of chromosomes 9 and 10, TP53 mutation), and overall survival (OS). RESULTS: TERT promoter mutations (TERTp-mut) were found in 299/395 glioblastomas (75.7%) and were associated with an older age (median 59.6 for TERTp-mut vs. 53.6 years for TERT promoter wild type (TERTp-wt) p < 0.0001). TERTp-mut was an independent factor of poor prognosis (OS= 13.8 vs. 18.4 months), in both IDH mutated (OS= 13.8 vs. 37.6 months, p= 0.022) and IDH wild type (IDHwt) GBM (OS= 13.7 vs. 17.5 months, p= 0.006). TERTp-mut was associated with IDH-wt and EGFR amplification (EGFR-amp) status. In TERTp-wt group, OS was twice longer in EGFR wt than in EGFR-amp GBM (OS= 26.6 vs. 13.3 months; p= 0.005). In the EGFR-wt group, TERTp-wt patients had a significantly better outcome (OS= 26.3 vs. 12.5 months; p< 0.0001), whereas in the EGFR-amp group, TERTp-mut patients survived longer (OS = 15.8 vs. 13.3 months; p= 0.05). Taken together, the absence of both EGFR-amp and Tertp-mut is associated with longer survival in glioblastoma patients (26.5 months for IDH-wt, 36.7 months for IDH-mut patients). CONCLUSIONS: The analysis of TERT promoter mutations, in combination with EGFR amplification and IDH mutation status, refines the prognostic classification of GBM.
Abstract
BACKGROUND
Spinal ependymomas (SP-EPN) are group of primary central nervous system tumors recently re-classified by the WHO (CNS5 2021), located in spinal cord. SP-EPN are grade 2-3 tumors, ...found mainly in cervical and thoracic region, characterized mostly by NF2 mutations and classical histology: grade 3 tumors present also microvascular proliferation, necrosis and high mitotic rate. Recently, a novel subtype was discovered with a unique methylation profile (SP-EPN-MYCN) and characterized by the amplification of MYCN gene, grade 3 histology and a very aggressive behavior. Treatment of these tumors remains challenging: gross-total resection is not often achieved and radiation failed to give sacceptable results. Besides, no prognostic factors except the mitotic index and tumor location, are available, thus, new diagnostic and prognostic biomarkers would be very useful for their accurate classification and management.
MATERIAL AND METHODS
We have collected 170 patients operated at our Institute from 1997 to 2019 of spinal ependymomas located in the cervical and thoracic region, excluded conus/filum mixopapillary ones. All tumors were revised according to the new WHO CNS5 2021 classification. In a cohort of 50 grade 2/3 SP-EPN we have evaluated by immunohistochemistry the expression of MYCN, H3K27me3, CDK4 and EZH2: the latter is a component of the PRC2 complex, which regulates the histone H3 methylation at Lys27 (K27) and recently described as a transcription factor which controls the expression of MYCN and CDK4 genes. We have also evaluated the amplification of MYCN and CDK4 genes by Copy Number Variation Assay and MLPA techniques. Clinical data were collected and related to the results obtained.
RESULTS
We have found strong overexpression of MYCN only in grade 3 SP-EPN (3/50), while grade 2 tumors showed low or no expression; amplification of MYCN gene was similarly confirmed by CNV assay and MLPA only in grade 3. Interestingly, also CDK4 overexpression was found only in grade 3 ependymomas (1/50), but it is expressed oppositely to MYCN: in tumors were MYCN is overexpressed, CDK4 was completely absent. Amplification of CDK4 gene was confirmed only in those with CDK4 overexpression. These results were both related to an interesting overexpression of EZH2 only in grade 3 SP-EPN (4/50), while H3K27me3 is expressed in all grades without differences. Finally, in our study both MYCN and CDK4-amplified ependymomas were related to a very aggressive behaviour and poor outcome with high recurrence rate, dissemination and metastases.
CONCLUSION
In this study we confirmed the prognostic role of MYCN as indicated by WHO classification and we have showed that CDK4 and EZH2 overexpression could be considered as new promising prognostic and predictive factors in SP-EPN. Since many trials with EZH2 and CDK4 inhibitors have been set up in the last years, these analyses could suggest a new therapeutic approach.
Abstract
BACKGROUND
NF2 related Schwannomatosis (NF2 -SCHW MIM # 101000) is a rare autosomal dominant familial cancer syndromes caused by mutations in the NF2 gene, mainly due to NF2 point mutations ...or intragenic deletions. NF2 patients. In 95% of patients, bilateral vestibular schwannomas are present, but NF2 -SCHW patients can develop other tumors and show ophthalmic and dermatological signs. Several studies established a genotype-phenotype correlations; the UK NF2 Reference Group proposed a Genetic Severity Score (GSS) based on the type and location of NF2 germline variant observed. Catasus et al. after validation of the score in a Spanish cohort suggested a new score based also on a functional assay of Merlin and its downstream pathways (FGSS). Recently Teranish et al. used targeted deep sequencing to predict functional prognosis in those patients.
MATERIAL AND
methods 70 patients (median age 40) were identified by scanning the electronic NF2-SCHW patient database at Fondazione IRCCS C. Besta, where the patients had undergone full neurological, ophthalmic, and audiological assessment. The median follow-up was 14 yrs. Clinical diagnosis was established following the Updated diagnostic criteria and nomenclature for neurofibromatosis type 2 and schwannomatosis”. All patients underwent NF2, SMARCB1 and LZTR1 mutational screening by NGS and MPLA analysis using blood DNA or the tissue of two different tumors when available.NF2 gene germline pathogenic were found in 45 subjects (64%), in most cases NF2 point mutations, but in 4 cases and whole gene deletions was observed and in 2 a ring NF2 chromosome was identified, in four cases a mosaic NF2-SCH was identified and in 21 (30%) patients no pathogenic variant was found. We assessed NF2-SCHW clinical phenotype in relation to the UK GSS and FGSS to validate their use as clinical and research tools, despite the significant phenotypic variability observed.
RESULTS
The disease outcome differed significantly depending both on clinicaland genetic factors. Among these factors,” Age of symptom onset” “Truncating”, “Mosaic”, and “whole gene deletion” had the most significant effects on functional disability. Conclusion GSS and FGSS showed significant correlation with several measures, allowing stratification of patients with severe and mild disease but not with moderate phenotype. Furthermore, we provided evidence on correlation between whole NF2 deletion extent and phenotype severity. Large cohorts of NF2-SCHW patients are needed to identify more accurate scores, becoming useful tools for patient management.
Abstract
BACKGROUND
As highlighted by the 2021 WHO classification of brain tumors, molecular characterization of gliomas is now critical to complement histopathological evaluation. However, ...intratumor heterogeneity may lead to surgical specimens not being fully representative of the whole tumor. Moreover, given the invasiveness of surgery, tissue analyses are not repeatable over time, thus limiting the possibility to monitor the response to therapies. In this context, we investigated the potential value of plasmatic cell-free DNA (PcfDNA) as a non-invasive ‘liquid biopsy’ marker of disease evolution.
MATERIAL AND METHODS
Patients’ blood was collected at 4 time points (TP), in parallel to clinical follow-up. A reproducible pipeline was optimized for blood withdrawal, centrifugation, plasma storage, cfDNA extraction from plasma by QIAamp MinElute ccfDNA Midi Kit (Quiagen) and cfDNA fluorometric quantification by Qubit (Thermo Fisher Scientific). MRI volumes were segmented in T1+contrast and T2-FLAIR sequences.
RESULTS
Fifty-four high-grade glioma patients and 14 healthy controls were enrolled. Blood samples were collected from all 54 patients at radiological diagnosis before surgery (TP0), from 33 patients after surgery (TP1), from 21 patients after radio-chemotherapy(TP2), from 10 patients at the first radiological progression (TP3). At T0, a significantly higher concentration of PcfDNA was detected in patients than in controls. IDH-wild-type gliomas showed a trend toward higher PcfDNA when compared with IDH-mutant gliomas. Digital-droplet PCR, performed at T0on PcfDNA of 4 patients with IDH-mutations in tumor tissues, identified the same IDH1-R132H mutation in all cases. When PcfDNA at TP0 was compared to that at TP1 of the same patient (n=33), there was a significant reduction of plasmatic cfDNA after surgery, mirroring the extensive tumor-resection shown by MRI. Finally, PcfDNA was evaluated in 10 patients until their radiological progression. Interestingly, PcfDNA levels not only followed the same trend of the volumes of T2-FLAIR hyperintensities and T1 contrast-enhancements, but were also mirrored by the evolution of KPS and NANO scores.
CONCLUSION
Preliminary results suggest that PcfDNA content may be an informative tool to complement MRI during the follow-up of high-grade gliomas.
Abstract
BACKGROUND
Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) has been recently recognized by 2021 WHO Central nervous system classification. It is an epileptogenic tumor ...type, affecting mostly children and young adults, with peculiar radiological, and pathomolecular features. PLNTY is a very rare tumor, described in only 52 cases up to now. Herein, we describe 13 patients with electro-clinical and neuroimaging findings, associated to histopathological and molecular findings.
MATERIAL AND METHODS
We selected PLNTY patients from our Cancer Registry (Apr 2017-Dec 2022), and collected electro-clinical, radiological and histo-molecular data. Minimum follow-up was 6 months. Exams included EEG, long-term scalp video-EEG, pre-surgical brain computer tomography and Magnetic Brain Imaging (MRI). Immunohistochemistry included CD34, IDH1-R132H, GFAP, synaptophysin, ATRX, p53 and FGFR3. IDH1-2, BRAF (V600E) sequencing, Kiaa1549:BRAF, FGFR3:TACC3, FGFR2:kii1598 and FGFR2:CTNNA3 fusion analyses will be performed.
RESULTS
We describe 13 patients, median age 20.6 years (range 12.3-46.4). Most patients showed memory/executive impairment and had epilepsy, with an onset from 5 months-21 years before surgery. The main feature of seizures was a difficult localization and even lateralization, both semiologically and electrographically. Post-surgical seizure control was excellent.The tumors (n=11/13 temporal) presented as solid or solid-cystic cortical mass with no mass effect and unclear hedges. Calcifications were present in 4, and cysts in 6 cases. Microscopically the tumors showed infiltrative growth pattern, oligodendroglial-like cells, strong and often diffuse CD34 immunostaining, and frequent intra-tumoral calcifications. Malformation of cortical development, namely FCD type IIIB, was associated to PLNTY in 2 cases. Proliferation activity (MIB-1 LI) was very low (1%) in all cases except one (MIB-1 LI which reached 3%).
CONCLUSION
This study significantly extends the number of reported PLNTY associated to epilepsy, mostly characterized by bilateral interictal epileptiform discharges and difficult to lateralize seizures.The MRI features were heterogeneous and the differential diagnosis should include also dysplasia and glioneuronal tumors. PLNTY, despite its name, occurs also in adults, and electro-clinical and radiological diagnosis can be challenging. As recently described, PLNTY can show the MAPK pathway activating alterations, that are under investigation in our cohort to eventually clarify their role in the evolution of the disease.
SUPPORT
the study is partially supported by the Health Italian Minister (RC).
Abstract
BACKGROUND
Several cancers with the BRAF V600E mutations have been successfully treated with targeted therapy. Pleomorphic xanthoastrocytoma (PXA) is a rare brain tumor, with an incidence of ...0.07cases per 100,000. The BRAFV600 mutation is present in 38–60% of PXA. Typical treatment is gross total resection, followed by radiotherapy and cytotoxic chemotherapy at recurrence
MATERIAL AND METHODS
Two cases are described.
RESULTS
The first case is a 37 old man with a left temporal lobe lesion who underwent a craniotomy with total tumor resection. Histological diagnosis was PXA WHO grade 2with BRAF V600E mutation.Five months after, MR imaging of his brain and spine showed tumor progression with extensive leptomeningeal disease. The patient received adjuvant brain and spinal radiotherapy Two weeks after, due to rapid clinical worsening he had a new brain and spinal MRI showing hydrocephalus and progression of the pachymeningeal-based masses and received an emergency ventricular -peritoneal shunt. Given the genetic analysis, the extent of disease and rapidity of the progression, BRAF and MEK inhibitors, dabrafenib (150 mg, twice daily) and trametinib (2 mg, daily) were started. Remarkably, within 2 week of initiating dual-targeted therapy, the patient experienced a dramatic improvement in consciousness and overall strength; brainand spinal MRI revealed initial reduction of the leptomenigeal enhacement and no evidence of progression of the intraparenchymal disease. The therapy was well-tolerated. Currently, after sixteen months,the patient remains on treatment with a consistent functional status improvement and no radiological evidence of disease progression. The second case is a 51 old women who developed leptomeningeal carcinomatosis seven year after resection of a frontal left PXA WHO grade 2 with BRAFv600E mutation. The patient had received brain radiotherapy five years after diagnosis and Cyber Knife for tumor progression. Ten months later MR imaging of his brain and spine showed tumor progression with extensive leptomeningeal disease, she was treated with temozolomide for 8 after clinical and radiological worsening she had a second surgery with resection of recurrent frontale left lesion Histopathology PXA WHO grade 2 with BRAF V600E mutation. She developed hydrocephalus, received an emergency ventricular -peritoneal shunt. BRAF and MEK inhibitors, dabrafenib (150 mg, twice daily) and trametinib (2 mg, daily) were started three months ago with initial clinical benefit
CONCLUSION
All patients with PXA should be tested for the BRAFV600 mutation, since, in these cases, targeted therapy with BRAF and MEK inhibitors seems to be a useful option for salvage treatment.
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