A multi-stem cell basis for craniosynostosis and calvarial mineralization.

Craniosynostosis is a group of disorders of premature calvarial suture fusion. The identity of the calvarial stem cells (CSCs) that produce fusion-driving osteoblasts in craniosynostosis remains poorly understood. Here we show that both physiologic calvarial mineralization and pathologic calvarial fusion in craniosynostosis reflect the interaction of two separate stem cell lineages; a previously identified cathepsin K (CTSK) lineage CSC1 (CTSK+ CSC) and a separate discoidin domain-containing receptor 2 (DDR2) lineage stem cell (DDR2+ CSC) that we identified in this study. Deletion of Twist1, a gene associated with craniosynostosis in humans2,3, solely in CTSK+ CSCs is sufficient to drive craniosynostosis in mice, but the sites that are destined to fuse exhibit an unexpected depletion of CTSK+ CSCs and a corresponding expansion of DDR2+ CSCs, with DDR2+ CSC expansion being a direct maladaptive response to CTSK+ CSC depletion. DDR2+ CSCs display full stemness features, and our results establish the presence of two distinct stem cell lineages in the sutures, with both populations contributing to physiologic calvarial mineralization. DDR2+ CSCs mediate a distinct form of endochondral ossification without the typical haematopoietic marrow formation. Implantation of DDR2+ CSCs into suture sites is sufficient to induce fusion, and this phenotype was prevented by co-transplantation of CTSK+ CSCs. Finally, the human counterparts of DDR2+ CSCs and CTSK+ CSCs display conserved functional properties in xenograft assays. The interaction between these two stem cell populations provides a new biologic interface for the modulation of calvarial mineralization and suture patency.

MRI Is a DNA Damage Response Adaptor during Classical Non-homologous End Joining.

The modulator of retrovirus infection (MRI or CYREN) is a 30-kDa protein with a conserved N-terminal Ku-binding motif (KBM) and a C-terminal XLF-like motif (XLM). We show that MRI is intrinsically disordered and interacts with many DNA damage response (DDR) proteins, including the kinases ataxia telangiectasia mutated (ATM) and DNA-PKcs and the classical non-homologous end joining (cNHEJ) factors Ku70, Ku80, XRCC4, XLF, PAXX, and XRCC4. MRI forms large multimeric complexes that depend on its N and C termini and localizes to DNA double-strand breaks (DSBs), where it promotes the retention of DDR factors. Mice deficient in MRI and XLF exhibit embryonic lethality at a stage similar to those deficient in the core cNHEJ factors XRCC4 or DNA ligase IV. Moreover, MRI is required for cNHEJ-mediated DSB repair in XLF-deficient lymphocytes. We propose that MRI is an adaptor that, through multivalent interactions, increases the avidity of DDR factors to DSB-associated chromatin to promote cNHEJ.

Grading meningiomas utilizing multiparametric MRI with inclusion of susceptibility weighted imaging and quantitative susceptibility mapping.

BACKGROUND AND PURPOSE: The ability to predict high-grade meningioma preoperatively is important for clinical surgical planning. The purpose of this study is to evaluate the performance of comprehensive multiparametric MRI, including susceptibility weighted imaging (SWI) and quantitative susceptibility mapping (QSM) in predicting high-grade meningioma both qualitatively and quantitatively. METHODS: Ninety-two low-grade and 37 higher grade meningiomas in 129 patients were included in this study. Morphological characteristics, quantitative histogram analysis of QSM and ADC images, and tumor size were evaluated to predict high-grade meningioma using univariate and multivariate analyses. Receiver operating characteristic (ROC) analyses were performed on the morphological characteristics. Associations between Ki-67 proliferative index (PI) and quantitative parameters were calculated using Pearson correlation analyses. RESULTS: For predicting high-grade meningiomas, the best predictive model in multivariate logistic regression analyses included calcification (ß=0.874, P=0.110), peritumoral edema (ß=0.554, P=0.042), tumor border (ß=0.862, P=0.024), tumor location (ß=0.545, P=0.039) for morphological characteristics, and tumor size (ß=4×10-5, P=0.004), QSM kurtosis (ß=-5×10-3, P=0.058), QSM entropy (ß=-0.067, P=0.054), maximum ADC (ß=-1.6×10-3, P=0.003), ADC kurtosis (ß=-0.013, P=0.014) for quantitative characteristics. ROC analyses on morphological characteristics resulted in an area under the curve (AUC) of 0.71 (0.61-0.81) for a combination of them. There were significant correlations between Ki-67 PI and mean ADC (r=-0.277, P=0.031), 25th percentile of ADC (r=-0.275, P=0.032), and 50th percentile of ADC (r=-0.268, P=0.037). CONCLUSIONS: Although SWI and QSM did not improve differentiation between low and high-grade meningiomas, combining morphological characteristics and quantitative metrics can help predict high-grade meningioma.

Integrated PET-MRI for Glioma Surveillance: Perfusion-Metabolism Discordance Rate and Association With Molecular Profiling.

OBJECTIVE: Both 18F-FDG PET and perfusion MRI are commonly used techniques for posttreatment glioma surveillance. Using integrated PET-MRI, we assessed the rate of discordance between simultaneously acquired FDG PET images and dynamic contrast-enhanced (DCE) perfusion MR images and determined whether tumor genetics predicts discordance. MATERIALS AND METHODS: Forty-one consecutive patients with high-grade gliomas (20 with grade IV gliomas and 21 with grade III gliomas) underwent a standardized tumor protocol performed using an integrated 3-T PET-MRI scanner. Quantitative measures of standardized uptake value, plasma volume, and permeability were obtained from segmented whole-tumor volumes of interest and targeted ROIs. ROC curve analysis and the Youden index were used to identify optimal cutoffs for FDG PET and DCE-MRI. Two-by-two contingency tables and percent agreement were used to assess accuracy and concordance. Twenty-six patients (63%) from the cohort underwent next-generation sequencing for tumor genetics. RESULTS: The best-performing FDG PET and DCE-MRI cutoffs achieved sensitivities of 94% and 91%, respectively; specificities of 56% and 89%, respectively; and accuracies of 80% and 83%, respectively. FDG PET and DCE-MRI findings were discordant for 11 patients (27%), with DCE-MRI findings correct for six of these patients (55%). Tumor grade, tumor volume, bevacizumab exposure, and time since radiation predicted discordance between FDG PET and DCE-MRI findings, with an ROC AUC value of 0.78. Isocitrate dehydrogenase gene and receptor tyrosine kinase gene pathway mutations increased the ROC AUC value to 0.83. CONCLUSION: FDG PET and DCE-MRI show comparable accuracy and sensitivity in identifying tumor progression. These modalities were shown to have discordant findings for more than a quarter of the patients assessed. Tumor genetics may contribute to perfusion-metabolism discordance, warranting further investigation.

Dynamic contrast-enhanced magnetic resonance imaging perfusion characteristics in meningiomas treated with resection and adjuvant radiosurgery.

OBJECTIVEThere is a need for advanced imaging biomarkers to improve radiation treatment planning and response assessment. T1-weighted dynamic contrast-enhanced perfusion MRI (DCE MRI) allows quantitative assessment of tissue perfusion and blood-brain barrier dysfunction and has entered clinical practice in the management of primary and secondary brain neoplasms. The authors sought to retrospectively investigate DCE MRI parameters in meningiomas treated with resection and adjuvant radiation therapy using volumetric segmentation.METHODSA retrospective review of more than 300 patients with meningiomas resected between January 2015 and December 2018 identified 14 eligible patients with 18 meningiomas who underwent resection and adjuvant radiotherapy. Patients were excluded if they did not undergo adjuvant radiation therapy or DCE MRI. Demographic and clinical characteristics were obtained and compared to DCE perfusion metrics, including mean plasma volume (vp), extracellular volume (ve), volume transfer constant (Ktrans), rate constant (kep), and wash-in rate of contrast into the tissue, which were derived from volumetric analysis of the enhancing volumes of interest.RESULTSThe mean patient age was 64 years (range 49-86 years), and 50% of patients (7/14) were female. The average tumor volume was 8.07 cm3 (range 0.21-27.89 cm3). The median Ki-67 in the cohort was 15%. When stratified by median Ki-67, patients with Ki-67 greater than 15% had lower median vp (0.02 vs 0.10, p = 0.002), and lower median wash-in rate (1.27 vs 4.08 sec-1, p = 0.04) than patients with Ki-67 of 15% or below. Logistic regression analysis demonstrated a statistically significant, moderate positive correlation between ve and time to progression (r = 0.49, p < 0.05). Furthermore, there was a moderate positive correlation between Ktrans and time to progression, which approached, but did not reach, statistical significance (r = 0.48, p = 0.05).CONCLUSIONSThis study demonstrates a potential role for DCE MRI in the preoperative characterization and stratification of meningiomas, laying the foundation for future prospective studies incorporating DCE as a biomarker in meningioma diagnosis and treatment planning.

Genomic profile of a primary squamous cell carcinoma arising from malignant transformation of a pineal epidermoid cyst.

Malignant transformation of intracranial epidermoid cysts is a rare occurrence. We present the second case of such an event occurring in the pineal region and the first case sent for detailed genomic profiling. MRI demonstrated two lesions: a cyst in a quadrigeminal cistern with restricted diffusion on DWI-weighted images and an adjacent, peripherally enhancing tumor with cerebellar infiltration. Both the lesions were completely resected with a small residual of the epidermoid cyst. The final pathology of both lesions was consistent with epidermoid cyst and squamous cell carcinoma (SCC), respectively. The tumor specimen was sent for comprehensive genomic profiling which revealed stable microsatellite status and loss of CDKN2A/B, MTAP (exons 2-8), and PTEN (exons 6-9). Although reports of primary SCC originating from the epidermoid cyst have been previously described, this is the first description of the genomic profile of such a tumor.

BRAF V600E mutant papillary craniopharyngiomas: a single-institutional case series.

PURPOSE: To describe the clinical, radiographic and surgical outcomes in a cohort of patients with BRAF V600E mutant papillary craniopharyngiomas. METHODS: A retrospective review was performed to identify all patients with a histological diagnosis of CP operated upon at a single institution between 2005 and 2017. All cases with adequate material were sequenced to confirm the presence of BRAF V600E mutation. RESULTS: Sixteen patients were included in the present study. Approach was endoscopic endonasal (EEA) in 14 and transcranial (TCA) in 2. All patients were adult with an average age of 50 years (24-88). Radiographic review demonstrated that the majority (93.7%) were suprasellar and twelve (75%) had third ventricular involvement. No tumor showed evidence of calcifications and 68.7% were mixed solid-cystic. All patients had some evidence of hypopituitarism and 62.5% had hypothalamic disturbances. GTR was achieved in 11/14 (78.6%) EEA and 0/2 (0%) TCA (p < 0.05). The mean length of stay was 17.5 days in the TCA group and 7.6 days in the EEA group (p < 0.05). There were no CSF leaks. Post-operatively, eleven (68.7%) developed new DI or new hypopituitarism. Nine increased their BMI with a mean increase of 12.3%, whereas six patients lost weight with a mean decrease of 5.3%. CONCLUSIONS: BRAF V600E mutant papillary tumors represent a clearly distinct clinical-pathological entity of craniopharyngiomas. These are generally non-calcified suprasellar tumors that occur in adults. These distinct characteristics may someday lead to upfront chemotherapy. When surgery is necessary, EEA may be preferred over TCA.

Long-term benefit of intra-arterial bevacizumab for recurrent glioblastoma.

OBJECTIVE: Standard treatment for recurrent GBM is not yet established. We present a case demonstrating the benefit of intra-arterial (IA) bevacizumab with blood brain barrier disruption (BBBD) for the treatment of recurrent GBM. A 31 year-old man diagnosed with GBM, following primary resection, received temozolomide. After a second resection, he received one dose of IA bevacizumab with BBBD using mannitol, preventing regrowth for 2.5 years. Following tumor regrowth, the patient received another dose of IA bevacizumab with BBBD, which has prevented regrowth for another year.

MRI-localized biopsies reveal subtype-specific differences in molecular and cellular composition at the margins of glioblastoma.

Glioblastomas (GBMs) diffusely infiltrate the brain, making complete removal by surgical resection impossible. The mixture of neoplastic and nonneoplastic cells that remain after surgery form the biological context for adjuvant therapeutic intervention and recurrence. We performed RNA-sequencing (RNA-seq) and histological analysis on radiographically guided biopsies taken from different regions of GBM and showed that the tissue contained within the contrast-enhancing (CE) core of tumors have different cellular and molecular compositions compared with tissue from the nonenhancing (NE) margins of tumors. Comparisons with the The Cancer Genome Atlas dataset showed that the samples from CE regions resembled the proneural, classical, or mesenchymal subtypes of GBM, whereas the samples from the NE regions predominantly resembled the neural subtype. Computational deconvolution of the RNA-seq data revealed that contributions from nonneoplastic brain cells significantly influence the expression pattern in the NE samples. Gene ontology analysis showed that the cell type-specific expression patterns were functionally distinct and highly enriched in genes associated with the corresponding cell phenotypes. Comparing the RNA-seq data from the GBM samples to that of nonneoplastic brain revealed that the differentially expressed genes are distributed across multiple cell types. Notably, the patterns of cell type-specific alterations varied between the different GBM subtypes: the NE regions of proneural tumors were enriched in oligodendrocyte progenitor genes, whereas the NE regions of mesenchymal GBM were enriched in astrocytic and microglial genes. These subtype-specific patterns provide new insights into molecular and cellular composition of the infiltrative margins of GBM.

VZV, temporal arteritis, and clinical practice: False positive immunohistochemical detection due to antibody cross-reactivity.

Varicella Zoster Virus (VZV) antigen has been reported to be present in the majority of temporal artery biopsies with implications for antiviral treatment in patients with giant cell arteritis. Using immunohistochemistry with VZV antibodies we found reactivity present in diverse myocyte types (smooth, skeletal and cardiac), diverse arteries (including temporal, coronary, and vertebral) and diverse clinical settings. This phenomenon is likely due to shared epitopes between VZV proteins and muscle elements and not due to actual VZV infection. We conclude that VZV immunohistochemistry should be used with caution for screening of VZV infection in the setting of temporal artery biopsies.

Toxicity evaluation of convection-enhanced delivery of small-molecule kinase inhibitors in naïve mouse brainstem.

PURPOSE: Diffuse intrinsic pontine gliomas (DIPGs) are inoperable and lethal high-grade gliomas lacking definitive therapy. Platelet-derived growth factor receptor (PDGFR) and its downstream signaling molecules are the most commonly overexpressed oncogenes in DIPG. This study tested the effective concentration of PDGFR pathway inhibitors in cell culture and then toxicity of these small-molecule kinase inhibitors delivered to the mouse brainstem via convection-enhanced delivery (CED) for potential clinical application. METHODS: Effective concentrations of small-molecule kinase inhibitors were first established in cell culture from a mouse brainstem glioma model. Sixteen mice underwent CED, a local drug delivery technique, of saline or of single and multidrug combinations of dasatinib (2 M), everolimus (20 M), and perifosine (0.63 mM) in the pons. Animals were kept alive for 3 days following the completion of infusion. RESULTS: No animals displayed any immediate or delayed neurological deficits postoperatively. Histological analysis revealed edema, microgliosis, acute inflammation, and/or axonal injury in the experimental animals consistent with mild acute drug toxicity. CONCLUSIONS: Brainstem CED of small-molecule kinase inhibitors in the mouse did not cause serious acute toxicities. Future studies will be necessary to evaluate longer-term safety to prepare for potential clinical application.

2021 World Health Organization Classification of Brain Tumors.

OBJECTIVE: The classification of brain tumors is a rapidly evolving field that requires extensive integration of molecular diagnostic findings from an expanding set of platforms and assays. This article summarizes the schema presented in the 5th edition of the World Health Organization (WHO) classification of central nervous system (CNS) tumors while highlighting diagnostic molecular findings and discussing the strengths and weaknesses of commonly available testing modalities. LATEST DEVELOPMENTS: Several major changes in practice were introduced with the 5th edition of the CNS WHO classification, including molecular grading of adult diffuse gliomas, the introduction of many new entities within the spectrum of pediatric gliomas and glioneuronal tumors, and the widespread adoption of methylation classes as useful or even necessary diagnostic criteria. Additionally, several revisions to nomenclature (eg, IDH-mutant gliomas) were introduced for simplicity and to disambiguate from other tumor types. ESSENTIAL POINTS: The classification of brain tumors continues to grow in complexity alongside our improved understanding of their nuanced molecular underpinnings.

Durability of an endoscopic management strategy for recurrent choroid plexus carcinoma with a comprehensive molecular characterization: illustrative case.

OBJECTIVE: Choroid plexus carcinoma (CPC) is a rare, primarily intraventricular neoplasm. Extent of resection correlates with improved outcomes but is limited due to tumor vascularity and size. Evidence on optimal surgical management and molecular drivers of recurrence remains limited. Here the authors characterize a case of multiply recurrent CPC treated with sequential endoscopic removals over 10 years and highlight its genomic properties. OBSERVATIONS: Five years after standard treatment, a 16-year-old female presented with a distant intraventricular recurrence of CPC. Whole exome sequencing revealed NF1, PER1, and SLC12A2 mutations, FGFR3 gain, and no TP53 alterations. Repeat sequencing on recurrences 4 and 5 years later showed persistent NF1 and FGFR3 alterations. Methylation profiling was consistent with plexus tumor, subclass pediatric B. Short-term magnetic resonance imaging detected four total isolated recurrences, all treated with complete endoscopic resections at 5, 6.5, 9, and 10 years after initial diagnosis. Mean hospital stay for all recurrences was 1 day with no complications. LESSONS: The authors describe a patient with four isolated recurrences of CPC over a decade, each treated with complete endoscopic removal, and identify unique molecular alterations that persisted without TP53 alterations. These outcomes support frequent neuroimaging to facilitate endoscopic surgical removal following early detection of CPC recurrence.

Polymorphous low-grade neuroepithelial tumor of the young with FGFR3-TACC3 fusion mimicking high-grade glioma: case report and series of high-grade correlates.

Background: Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described entity that can mimic high-grade glioma (HGG) in histologic and molecular features; however, factors predicting aggressive behavior in these tumors are unclear. Methods: We present an indolent neuroepithelial neoplasm in a 59-year-old female with imaging initially suggestive of HGG, and a series of adult patients with HGG harboring FGFR3-TACC3 fusions are also presented for comparison. Results: Pathology in the case patient revealed low-grade cytomorphology, microcalcifications, unusual neovascularization, and a low proliferation index. The lesion was diffusely CD34+ and harbored an FGFR3-TACC3 fusion and TERT promoter mutation. A diagnosis of PLNTY was therefore favored and the patient was observed with no progression at 15-month follow-up. In patients with HGG with FGFR3-TACC3 fusions, molecular findings included IDH-wildtype status, absence of 1p19q codeletion, CDKN2A loss, TERT promoter mutations and lack of MGMT promoter methylation. These patients demonstrated a median 15-month overall survival and a 6-month progression-free survival. Conclusion: PLNTY is a rare low-grade entity that can display characteristics of HGG, particularly in adults. Presence of FGFR3-TACC3 fusions and other high-grade features should raise concern for a more malignant precursor lesion when a diagnosis of PLNTY is considered.

Pediatric Postmortem Tissue Donation in the Confines of a Pandemic: A Model of Collaboration.

BACKGROUND: Obtaining postmortem tissue from pediatric oncology patients is critical to research and may help grieving families heal. Since 2019, the national Gift from a Child program has made significant progress in collecting postmortem tissue from pediatric patients with central nervous system tumors to advance research. This progress was at risk during the onset of the severe acute respiratory syndrome coronavirus 2 pandemic, when some autopsy programs came to a halt. METHODS: We retrospectively reviewed autopsies of four patients treated at Memorial Sloan Kettering Cancer Center who underwent postmortem examination at Weill Cornell Medicine from June 2020 to March 2021. We collected patient demographics, Do not resuscitate status, time of death and procedure, restrictions due to the coronavirus disease 2019 (COVID-19) pandemic, and results of the tissue analysis. RESULTS: Three of four specimens were processed within 12 hours of the time of death. Two families required interpreter services to obtain consent. In all cases, tumor aliquots were flash frozen for further study. Cell line generation was successful in one case. All families expressed gratitude both for the opportunity to participate and for the handling of the procedures. CONCLUSIONS: Despite the sensitive nature of these cases and the challenges presented by COVID-19 restrictions, clinicians should offer the option of a rapid autopsy to caregivers of pediatric patients based on the scientific need and the positive effect it has on grieving families. This article outlines the logistic efforts required for these donations to take place and provides a framework for providers to offer rapid autopsy as an option for families through this program.

Insulin feedback is a targetable resistance mechanism of PI3K inhibition in glioblastoma.

BACKGROUND: Insulin feedback is a critical mechanism responsible for the poor clinical efficacy of phosphatidylinositol 3-kinase (PI3K) inhibition in cancer, and hyperglycemia is an independent factor associated with poor prognosis in glioblastoma (GBM). We investigated combination anti-hyperglycemic therapy in a mouse model of GBM and evaluated the association of glycemic control in clinical trial data from patients with GBM. METHODS: The effect of the anti-hyperglycemic regimens, metformin and the ketogenic diet, was evaluated in combination with PI3K inhibition in patient-derived GBM cells and in an orthotopic GBM mouse model. Insulin feedback and the immune microenvironment were retrospectively evaluated in blood and tumor tissue from a Phase 2 clinical trial of buparlisib in patients with recurrent GBM. RESULTS: We found that PI3K inhibition induces hyperglycemia and hyperinsulinemia in mice and that combining metformin with PI3K inhibition improves the treatment efficacy in an orthotopic GBM xenograft model. Through examination of clinical trial data, we found that hyperglycemia was an independent factor associated with poor progression-free survival in patients with GBM. We also found that PI3K inhibition increased insulin receptor activation and T-cell and microglia abundance in tumor tissue from these patients. CONCLUSION: Reducing insulin feedback improves the efficacy of PI3K inhibition in GBM in mice, and hyperglycemia worsens progression-free survival in patients with GBM treated with PI3K inhibition. These findings indicate that hyperglycemia is a critical resistance mechanism associated with PI3K inhibition in GBM and that anti-hyperglycemic therapy may enhance PI3K inhibitor efficacy in GBM patients.

The importance of escalating molecular diagnostics in patients with low-grade pediatric brain cancer.

Pilocytic astrocytomas are the most common pediatric brain tumors, typically presenting as low-grade neoplasms. We report two cases of pilocytic astrocytoma with atypical tumor progression. Case 1 involves a 12-yr-old boy with an unresectable suprasellar tumor, negative for BRAF rearrangement but harboring a BRAF p.V600E mutation. He experienced tumor size reduction and stable disease following dabrafenib treatment. Case 2 describes a 6-yr-old boy with a thalamic tumor that underwent multiple resections, with no actionable driver detected using targeted next-generation sequencing. Whole-genome and RNA-seq analysis identified an internal tandem duplication in FGFR1 and RAS pathway activation. Future management options include FGFR1 inhibitors. These cases demonstrate the importance of escalating molecular diagnostics for pediatric brain cancer, advocating for early reflexing to integrative whole-genome sequencing and transcriptomic profiling when targeted panels are uninformative. Identifying molecular drivers can significantly impact treatment decisions and improve patient outcomes.

Endoglin, a Novel Biomarker and Therapeutical Target to Prevent Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis.

PURPOSE: Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive soft-tissue sarcomas that lack effective treatments, underscoring the urgent need to uncover novel mediators of MPNST pathogenesis that may serve as potential therapeutic targets. Tumor angiogenesis is considered a critical event in MPNST transformation and progression. Here, we have investigated whether endoglin (ENG), a TGFß coreceptor with a crucial role in angiogenesis, could be a novel therapeutic target in MPNSTs. EXPERIMENTAL DESIGN: ENG expression was evaluated in human peripheral nerve sheath tumor tissues and plasma samples. Effects of tumor cell-specific ENG expression on gene expression, signaling pathway activation and in vivo MPNST growth and metastasis, were investigated. The efficacy of ENG targeting in monotherapy or in combination with MEK inhibition was analyzed in xenograft models. RESULTS: ENG expression was found to be upregulated in both human MPNST tumor tissues and plasma-circulating small extracellular vesicles. We demonstrated that ENG modulates Smad1/5 and MAPK/ERK pathway activation and pro-angiogenic and pro-metastatic gene expression in MPNST cells and plays an active role in tumor growth and metastasis in vivo. Targeting with ENG-neutralizing antibodies (TRC105/M1043) decreased MPNST growth and metastasis in xenograft models by reducing tumor cell proliferation and angiogenesis. Moreover, combination of anti-ENG therapy with MEK inhibition effectively reduced tumor cell growth and angiogenesis. CONCLUSIONS: Our data unveil a tumor-promoting function of ENG in MPNSTs and support the use of this protein as a novel biomarker and a promising therapeutic target for this disease.

Machine learning can aid in prediction of IDH mutation from H&E-stained histology slides in infiltrating gliomas.

While Machine Learning (ML) models have been increasingly applied to a range of histopathology tasks, there has been little emphasis on characterizing these models and contrasting them with human experts. We present a detailed empirical analysis comparing expert neuropathologists and ML models at predicting IDH mutation status in H&E-stained histology slides of infiltrating gliomas, both independently and synergistically. We find that errors made by neuropathologists and ML models trained using the TCGA dataset are distinct, representing modest agreement between predictions (human-vs.-human κ = 0.656; human-vs.-ML model κ = 0.598). While no ML model surpassed human performance on an independent institutional test dataset (human AUC = 0.901, max ML AUC = 0.881), a hybrid model aggregating human and ML predictions demonstrates predictive performance comparable to the consensus of two expert neuropathologists (hybrid classifier AUC = 0.921 vs. two-neuropathologist consensus AUC = 0.920). We also show that models trained at different levels of magnification exhibit different types of errors, supporting the value of aggregation across spatial scales in the ML approach. Finally, we present a detailed interpretation of our multi-scale ML ensemble model which reveals that predictions are driven by human-identifiable features at the patch-level.

Towards a single-assay approach: a combined DNA/RNA sequencing panel eliminates diagnostic redundancy and detects clinically-relevant fusions in neuropathology.

Since the introduction of integrated histological and molecular diagnoses by the 2016 World Health Organization (WHO) Classification of Tumors of the Nervous System, an increasing number of molecular markers have been found to have prognostic significance in infiltrating gliomas, many of which have now become incorporated as diagnostic criteria in the 2021 WHO Classification. This has increased the applicability of targeted-next generation sequencing in the diagnostic work-up of neuropathology specimens and in addition, raises the question of whether targeted sequencing can, in practice, reliably replace older, more traditional diagnostic methods such as immunohistochemistry and fluorescence in-situ hybridization. Here, we demonstrate that the Oncomine Cancer Gene Mutation Panel v2 assay targeted-next generation sequencing panel for solid tumors is not only superior to IHC in detecting mutation in IDH1/2 and TP53 but can also predict 1p/19q co-deletion with high sensitivity and specificity relative to fluorescence in-situ hybridization by looking at average copy number of genes sequenced on 1p, 1q, 19p, and 19q. Along with detecting the same molecular data obtained from older methods, targeted-next generation sequencing with an RNA sequencing component provides additional information regarding the presence of RNA based alterations that have diagnostic significance and possible therapeutic implications. From this work, we advocate for expanded use of targeted-next generation sequencing over more traditional methods for the detection of important molecular alterations as a part of the standard diagnostic work up for CNS neoplasms.