Prognostic value of cell-free DNA in cerebrospinal fluid from lung cancer patients with brain metastases during radiotherapy.

BACKGROUND: During the last decades, radiotherapy (RT) for non-small cell lung cancer (NSCLC) with brain metastases (BM) has been developed. However, the lack of predictive biomarkers for therapeutic responses has limited the precision treatment in NSCLC-BM. PATIENTS AND METHODS: In order to find the predictive biomarkers for RT, we investigated the influence of RT on the cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) and the frequency of T cell subsets of NSCLC patients with BM. A total of 19 patients diagnosed as NSCLC with BM were enrolled. The CSF from 19 patients and matched plasma samples from 11 patients were collected before RT, during RT, and after RT. The cfDNA from CSF and plasma were extracted, and the cerebrospinal fluid tumor mutation burden (cTMB) was calculated after through next-generation sequencing. The frequency of T cell subsets in peripheral blood was using flow cytometry. RESULTS: The detection rate of cfDNA was higher in CSF compared to plasma in the matched samples. The mutation abundance of cfDNA in CSF was decreased after RT. However, no significant difference was observed in cTMB before and after RT. Although the median intracranial progression-free survival (iPFS) has not yet been reached in patients with decreased or undetectable cTMB, there was a trend that these patients possessed longer iPFS compared to those with stable or increased cTMB (HR 0.28, 95% CI 0.07-1.18, P = 0.067). The proportion of CD4+T cells in peripheral blood was decreased after RT. CONCLUSION: Our study indicates that cTMB can serve as a prognostic biomarker in NSCLC patients with BMs.

Selective protection of normal cells from chemotherapy, while killing drug-resistant cancer cells.

Cancer therapy is limited by toxicity in normal cells and drug-resistance in cancer cells. Paradoxically, cancer resistance to certain therapies can be exploited for protection of normal cells, simultaneously enabling the selective killing of resistant cancer cells by using antagonistic drug combinations, which include cytotoxic and protective drugs. Depending on the mechanisms of drug-resistance in cancer cells, the protection of normal cells can be achieved with inhibitors of CDK4/6, caspases, Mdm2, mTOR, and mitogenic kinases. When normal cells are protected, the selectivity and potency of multi-drug combinations can be further enhanced by adding synergistic drugs, in theory, eliminating the deadliest cancer clones with minimal side effects. I also discuss how the recent success of Trilaciclib may foster similar approaches into clinical practice, how to mitigate systemic side effects of chemotherapy in patients with brain tumors and how to ensure that protective drugs would only protect normal cells (not cancer cells) in a particular patient.

Immunological and tumor-intrinsic mechanisms mediate the synergistic growth suppression of experimental glioblastoma by radiotherapy and MET inhibition.

The hepatocyte growth factor (HGF)/MET signaling pathway has been proposed to be involved in the resistance to radiotherapy of glioblastoma via proinvasive and DNA damage response pathways.Here we assessed the role of the MET pathway in the response to radiotherapy in vitro and in vivo in syngeneic mouse glioma models. We find that the murine glioma cell lines GL-261, SMA-497, SMA-540 and SMA-560 express HGF and its receptor MET and respond to exogenous HGF with MET phosphorylation. Glioma cell viability or proliferation are unaffected by genetic or pharmacological MET inhibition using tepotinib or CRISPR/Cas9-engineered Met gene knockout and MET inhibition fails to sensitize glioma cells to irradiation in vitro. In contrast, the combination of tepotinib with radiotherapy prolongs survival of orthotopic SMA-560 or GL-261 glioma-bearing mice compared with radiotherapy or tepotinib treatment alone. Synergy is lost when such experiments are conducted in immunodeficient Rag1-/- mice, and, importantly, also when Met gene expression is disrupted in the tumor cells. Combination therapy suppresses a set of pro-inflammatory mediators including matrix metalloproteases that are upregulated by radiotherapy alone and that have been linked to poor outcome in glioblastoma. Several of these mediators are positively regulated by transforming growth factor (TGF)-ß, and pSMAD2 levels as a surrogate marker of TGF-ß pathway activity are suppressed by combination treatment. We conclude that synergistic suppression of experimental syngeneic glioma growth by irradiation and MET inhibition requires MET expression in the tumor as well as an intact immune system. Clinical evaluation of this combined strategy in newly diagnosed glioblastoma is warranted.

Pharmacogenomic profiling reveals molecular features of chemotherapy resistance in IDH wild-type primary glioblastoma.

BACKGROUND: Although temozolomide (TMZ) has been used as a standard adjuvant chemotherapeutic agent for primary glioblastoma (GBM), treating isocitrate dehydrogenase wild-type (IDH-wt) cases remains challenging due to intrinsic and acquired drug resistance. Therefore, elucidation of the molecular mechanisms of TMZ resistance is critical for its precision application. METHODS: We stratified 69 primary IDH-wt GBM patients into TMZ-resistant (n = 29) and sensitive (n = 40) groups, using TMZ screening of the corresponding patient-derived glioma stem-like cells (GSCs). Genomic and transcriptomic features were then examined to identify TMZ-associated molecular alterations. Subsequently, we developed a machine learning (ML) model to predict TMZ response from combined signatures. Moreover, TMZ response in multisector samples (52 tumor sectors from 18 cases) was evaluated to validate findings and investigate the impact of intra-tumoral heterogeneity on TMZ efficacy. RESULTS: In vitro TMZ sensitivity of patient-derived GSCs classified patients into groups with different survival outcomes (P = 1.12e-4 for progression-free survival (PFS) and 3.63e-4 for overall survival (OS)). Moreover, we found that elevated gene expression of EGR4, PAPPA, LRRC3, and ANXA3 was associated to intrinsic TMZ resistance. In addition, other features such as 5-aminolevulinic acid negative, mesenchymal/proneural expression subtypes, and hypermutation phenomena were prone to promote TMZ resistance. In contrast, concurrent copy-number-alteration in PTEN, EGFR, and CDKN2A/B was more frequent in TMZ-sensitive samples (Fisher's exact P = 0.0102), subsequently consolidated by multi-sector sequencing analyses. Integrating all features, we trained a ML tool to segregate TMZ-resistant and sensitive groups. Notably, our method segregated IDH-wt GBM patients from The Cancer Genome Atlas (TCGA) into two groups with divergent survival outcomes (P = 4.58e-4 for PFS and 3.66e-4 for OS). Furthermore, we showed a highly heterogeneous TMZ-response pattern within each GBM patient using in vitro TMZ screening and genomic characterization of multisector GSCs. Lastly, the prediction model that evaluates the TMZ efficacy for primary IDH-wt GBMs was developed into a webserver for public usage ( http://www.wang-lab-hkust.com:3838/TMZEP ). CONCLUSIONS: We identified molecular characteristics associated to TMZ sensitivity, and illustrate the potential clinical value of a ML model trained from pharmacogenomic profiling of patient-derived GSC against IDH-wt GBMs.

Gut microbiota mediated the individualized efficacy of Temozolomide via immunomodulation in glioma.

BACKGROUND: Temozolomide (TMZ) is the preferred chemotherapy strategy for glioma therapy. As a second-generation alkylating agent, TMZ provides superior oral bio-availability. However, limited response rate (less than 50%) and high incidence of drug resistance seriously restricts TMZ's application, there still lack of strategies to increase the chemotherapy sensitivity. METHODS: Luci-GL261 glioma orthotopic xenograft model combined bioluminescence imaging was utilized to evaluate the anti-tumor effect of TMZ and differentiate TMZ sensitive (S)/non-sensitive (NS) individuals. Integrated microbiomics and metabolomics analysis was applied to disentangle the involvement of gut bacteria in TMZ sensitivity. Spearman's correlation analysis was applied to test the association between fecal bacteria levels and pharmacodynamics indices. Antibiotics treatment combined TMZ treatment was used to confirm the involvement of gut microbiota in TMZ response. Flow cytometry analysis, ELISA and histopathology were used to explore the potential role of immunoregulation in gut microbiota mediated TMZ response. RESULTS: Firstly, gut bacteria composition was significantly altered during glioma development and TMZ treatment. Meanwhile, in vivo anti-cancer evaluation suggested a remarkable difference in chemotherapy efficacy after TMZ administration. Moreover, 16s rRNA gene sequencing and non-targeted metabolomics analysis revealed distinct different gut microbiota and immune infiltrating state between TMZ sensitive and non-sensitive mice, while abundance of differential gut bacteria and related metabolites was significantly correlated with TMZ pharmacodynamics indices. Further verification suggested that gut microbiota deletion by antibiotics treatment could accelerate glioma development, attenuate TMZ efficacy and inhibit immune cells (macrophage and CD8α+ T cell) recruitment. CONCLUSIONS: The current study confirmed the involvement of gut microbiota in glioma development and individualized TMZ efficacy via immunomodulation, hence gut bacteria may serve as a predictive biomarker as well as a therapeutic target for clinical TMZ application.

Quinolinate promotes macrophage-induced immune tolerance in glioblastoma through the NMDAR/PPARγ signaling axis.

There has been considerable scientific effort dedicated to understanding the biologic consequence and therapeutic implications of aberrant tryptophan metabolism in brain tumors and neurodegenerative diseases. A majority of this work has focused on the upstream metabolism of tryptophan; however, this has resulted in limited clinical application. Using global metabolomic profiling of patient-derived brain tumors, we identify the downstream metabolism of tryptophan and accumulation of quinolinate (QA) as a metabolic node in glioblastoma and demonstrate its critical role in promoting immune tolerance. QA acts as a metabolic checkpoint in glioblastoma by inducing NMDA receptor activation and Foxo1/PPARγ signaling in macrophages, resulting in a tumor supportive phenotype. Using a genetically-engineered mouse model designed to inhibit production of QA, we identify kynureninase as a promising therapeutic target to revert the potent immune suppressive microenvironment in glioblastoma. These findings offer an opportunity to revisit the biologic consequence of this pathway as it relates to oncogenesis and neurodegenerative disease and a framework for developing immune modulatory agents to further clinical gains in these otherwise incurable diseases.

Short Communication: Results of a Consensus Conference on Radiotherapy for Brain and Bone Metastases Within the Interreg-Project TreaT.

BACKGROUND/AIM: Differences between radiotherapy for metastases in Northern Germany and Southern Denmark were previously identified, which led to a consensus conference. PATIENTS AND METHODS: A consensus conference was held between three centers to harmonize radiotherapy regimens for bone and brain metastases. RESULTS: Centers agreed on 1×8 Gy for painful bone metastases in patients with poor or intermediate survival prognoses and 10×3 Gy for favorable-prognosis patients. For complicated bone metastases, 5-6×4 Gy was preferred for poor-prognosis, 10×3 Gy for intermediate-prognosis, and longer-course radiotherapy for favorable-prognosis patients. For ≥5 brain metastases, centers agreed on whole-brain irradiation (WBI) with 5×4 Gy in poor-prognosis and longer-course regimens in other patients. For single brain lesions and patients with 2-4 lesions and intermediate/favorable prognoses, fractionated stereotactic radiotherapy (FSRT) or radiosurgery were recommended. No consensus was reached for 2-4 lesions in poor-prognosis patients; two centers preferred FSRT, one center WBI. Preferred radiotherapy regimens were similar for different age groups including elderly and very elderly patients, but age-specific survival scores were recommended. CONCLUSION: The consensus conference was successful, since harmonization of radiotherapy regimens was achieved for 32 of 33 possible situations.

Supratentorial CNS-PNETs in children; a Swedish population-based study with molecular re-evaluation and long-term follow-up.

BACKGROUND: Molecular analyses have shown that tumours diagnosed as supratentorial primitive neuro-ectodermal tumours of the central nervous system (CNS-PNETs) in the past represent a heterogenous group of rare childhood tumours including high-grade gliomas (HGG), ependymomas, atypical teratoid/rhabdoid tumours (AT/RT), CNS neuroblastoma with forkhead box R2 (FOXR2) activation and embryonal tumour with multi-layered rosettes (ETMR). All these tumour types are rare and long-term clinical follow-up data are sparse. We retrospectively re-evaluated all children (0-18 years old) diagnosed with a CNS-PNET in Sweden during 1984-2015 and collected clinical data. METHODS: In total, 88 supratentorial CNS-PNETs were identified in the Swedish Childhood Cancer Registry and from these formalin-fixed paraffin-embedded tumour material was available for 71 patients. These tumours were histopathologically re-evaluated and, in addition, analysed using genome-wide DNA methylation profiling and classified by the MNP brain tumour classifier. RESULTS: The most frequent tumour types, after histopathological re-evaluation, were HGG (35%) followed by AT/RT (11%), CNS NB-FOXR2 (10%) and ETMR (8%). DNA methylation profiling could further divide the tumours into specific subtypes and with a high accuracy classify these rare embryonal tumours. The 5 and 10-year overall survival (OS) for the whole CNS-PNET cohort was 45% ± 12% and 42% ± 12%, respectively. However, the different groups of tumour types identified after re-evaluation displayed very variable survival patterns, with a poor outcome for HGG and ETMR patients with 5-year OS 20% ± 16% and 33% ± 35%, respectively. On the contrary, high PFS and OS was observed for patients with CNS NB-FOXR2 (5-year 100% for both). Survival rates remained stable even after 15-years of follow-up. CONCLUSIONS: Our findings demonstrate, in a national based setting, the molecular heterogeneity of these tumours and show that DNA methylation profiling of these tumours provides an indispensable tool in distinguishing these rare tumours. Long-term follow-up data confirms previous findings with a favourable outcome for CNS NB-FOXR2 tumours and poor chances of survival for ETMR and HGG.

The Health Care Utilization and Medical Costs in Long-Term Follow-Up of Children Diagnosed With Leukemia, Solid Tumor, or Brain Tumor: Population-Based Study Using the National Health Insurance Claims Data.

BACKGROUND: Childhood cancer survivors are at a high risk of medical consequences of their disease and treatment. There is growing information about the long-term health issues of childhood cancer survivors; however, there are very few studies describing the health care utilization and costs for this unique population. Understanding their utilization of health care services and costs will provide the basis for developing strategies to better serve these individuals and potentially reduce the cost. OBJECTIVE: This study aims to determine the utilization of health services and costs for long-term survivors of childhood cancer in Taiwan. METHODS: This is a nationwide, population-based, retrospective case-control study. We analyzed the claims data of the National Health Insurance that covers 99% of the Taiwanese population of 25.68 million. A total of 33,105 children had survived for at least 5 years after the first appearance of a diagnostic code of cancer or a benign brain tumor before the age of 18 years from 2000 to 2010 with follow-up to 2015. An age- and gender-matched control group of 64,754 individuals with no cancer was randomly selected for comparison. Utilization was compared between the cancer and no cancer groups by χ2 test. The annual medical expense was compared by the Mann-Whitney U test and Kruskal-Wallis rank-sum test. RESULTS: At a median follow-up of 7 years, childhood cancer survivors utilized a significantly higher proportion of medical center, regional hospital, inpatient, and emergency services in contrast to no cancer individuals: 57.92% (19,174/33,105) versus 44.51% (28,825/64,754), 90.66% (30,014/33,105) versus 85.70% (55,493/64,754), 27.19% (9000/33,105) versus 20.31% (13,152/64,754), and 65.26% (21,604/33,105) versus 59.36% (38,441/64,754), respectively (all P<.001). The annual total expense (median, interquartile range) of childhood cancer survivors was significantly higher than that of the comparison group (US $285.56, US $161.78-US $535.80 per year vs US $203.90, US $118.98-US $347.55 per year; P<.001). Survivors with female gender, diagnosis before the age of 3 years, and diagnosis of brain cancer or a benign brain tumor had significantly higher annual outpatient expenses (all P<.001). Moreover, the analysis of outpatient medication costs showed that hormonal and neurological medications comprised the 2 largest costs in brain cancer and benign brain tumor survivors. CONCLUSIONS: Survivors of childhood cancer and a benign brain tumor had higher utilization of advanced health resources and higher costs of care. The design of the initial treatment plan minimizing long-term consequences, early intervention strategies, and survivorship programs have the potential to mitigate costs of late effects due to childhood cancer and its treatment.

Multiple craniotomies in a single surgery - the resection of scattered brain metastases.

Patients with brain metastases (BM), who can benefit from resection of multiple scattered lesions, often will not be offered a procedure involving multiple craniotomies in one session due to the overall poor prognosis. However, carefully selected candidates may well benefit from the resection of multiple lesions using multiple craniotomies through a significantly shortened hospital stay, aggressive decompression, and rapid eligibility for adjuvant therapies. In this retrospective analysis, the records of patients, who were treated for multiple BM using one surgical session involving multiple craniotomies, were reviewed. A group of patients with multiple BM, whose surgery only involved one craniotomy, were assigned to a control group. Clinical and surgical characteristics, preoperative and postoperative Karnofsky Performance Scale (KPS), complication rate, preoperative tumor size, number of lesions, number of craniotomies, skin incisions, and intraoperative repositioning of patients were recorded. Thirty-three patients were included in the multiple-craniotomy group. Thirty patients underwent two craniotomies, while three cases involved three craniotomies. Seven patients (21%) were intraoperatively repositioned from a prone to a supine position, which required an average of 23.3 ± 9.3 min from wound closure to the following skin incision. Thirty-six patients with multiple BM and matching characteristics, who received only one craniotomy for the dominant lesion, served as the control group. No difference was detected in postoperative KPS (p = 0.269), complication rate (p = 0.612), rate of new postoperative neurological deficits (p = 0.278), length of intensive care unit (ICU) (p = 0.991), and hospital stay (p = 0.913). There was a significant difference in average preoperative tumor size (p = 0.002), duration of surgery (p < 0.001), and extent of resection (p = 0.002). In the age of personalized medicine, selected patient may benefit from a single surgery for BM using multiple craniotomies. This study shows no significant increase of the perioperative complication rate for surgeries with multiple craniotomies.

Radiotherapy, lymphopenia and improving the outcome for glioblastoma: a narrative review.

BACKGROUND AND OBJECTIVE: Standard treatment for glioblastoma includes maximal safe resection followed by adjuvant radiation and concurrent temozolomide for 6 weeks, followed by 6 months of maintenance temozolomide; additionally, concurrent high doses of corticosteroids are required for many patients to reduce intracranial pressure and reduce inflammatory side effects. This combination of cytotoxic therapies (including radiotherapy, temozolomide, and corticosteroids) often results in severe treatment-related lymphopenia that can persist beyond the duration of therapy. METHODS: Papers on treatment-related lymphopenia were retrieved to analyze the role of lymphocytes in tumor control, the role of radiotherapy in inducing lymphopenia, understand other contributing factors to lymphopenia and investigate strategies (including altered radiation approaches) that may reduce the impact of lymphopenia for patients with glioblastoma in the future. KEY CONTENT AND FINDINGS: Radiation, in particular, plays an important role in lymphopenia. Lymphocytes are considered the most radiosensitive cells in the human body, and ionizing radiation often results in apoptotic response and rapid death of lymphocytes within hours of exposure. As a result, radiotherapy can lead to systemic immunosuppression including lymphopenia which is permissive of tumor growth and is linked to impaired local control and reduced survival. For this reason, interactions between radiotherapy treatment and the immune response to tumor is the subject of active study. This study also explores promising lymphocyte-medicated immune therapies which have developed clinical use for many non-glioblastoma cancer types, with promising preclinical results in glioblastoma treatment. CONCLUSIONS: Limiting treatment-related lymphopenia is especially important in improving treatment outcomes for glioblastoma. Research on strategies to reduce the impact of lymphopenia may promote improved treatment outcomes for glioblastoma patients.

2021 updates to the World Health Organization classification of adult-type and pediatric-type diffuse gliomas: a clinical practice review.

In 2021, the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) underwent significant restructuring to incorporate additional molecular diagnostics, several newly recognized tumor types, and new grading schemes for existing tumor types. The 2021 CNS WHO classification further elaborates and integrates histopathologic and molecular diagnostic criteria to improve diagnostic classification. Furthermore, it is the hope that identification of molecular alterations in pediatric and adult tumors facilitates improved prognostic information and development of novel targeted therapies for adults and children with CNS tumors. In one of the largest changes in the new WHO classification, diffuse gliomas are divided into pediatric-type and adult-type gliomas to highlight our expanding knowledge of their different molecular drivers and prognostic associations. Several new pediatric-type diffuse low-grade gliomas are defined including (I) diffuse astrocytoma, MYB- or MYBL1-altered, (II) polymorphous low-grade neuroepithelial tumor of the young (PLNTY), and (III) diffuse low-grade glioma, MAPK-pathway altered. In addition, several new pediatric-type diffuse high-grade gliomas are recognized including (I) diffuse hemispheric glioma, H3 G34R-mutant (II) diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype, and (III) infant-type hemispheric glioma. These new tumor types have associated clinical, genetic and epigenetic features that are distinct from adult-type diffuse gliomas. This review provides an overview of updates in the 2021 CNS WHO classification specific to diffuse gliomas, with a particular focus on the histopathology and molecular findings of the newly described pediatric-type low-grade and high-grade gliomas.

Rab32 promotes glioblastoma migration and invasion via regulation of ERK/Drp1-mediated mitochondrial fission.

The highly widespread and infiltrative nature of glioblastoma multiforme (GBM) makes complete surgical resection hard, causing high recurrence rate and poor patients' prognosis. However, the mechanism underlying GBM migration and invasion is still unclear. In this study, we investigated the role of a Ras-related protein Rab32 on GBM and uncovered its underlying molecular and subcellular mechanisms that contributed to GBM aggressiveness. The correlation of Rab32 expression with patient prognosis and tumor grade was investigated by public dataset analysis and clinical specimen validation. The effect of Rab32 on migration and invasion of GBM had been evaluated using wound healing assay, cell invasion assay, as well as protein analysis upon Rab32 manipulations. Mitochondrial dynamics of cells upon Rab32 alterations were detected by immunofluorescence staining and western blotting. Both the subcutaneous and intracranial xenograft tumor model were utilized to evaluate the effect of Rab32 on GBM in vivo. The expression level of Rab32 is significantly elevated in the GBM, especially in the most malignant mesenchymal subtype, and is positively correlated with tumor pathological grade and poor prognosis. Knockdown of Rab32 attenuated the capability of GBM's migration and invasion. It also suppressed the expression levels of invasion-related proteins (MMP2 and MMP9) as well as mesenchymal transition markers (N-cadherin, vimentin). Interestingly, Rab32 transported Drp1 to mitochondrial from the cytoplasm and modulated mitochondrial fission in an ERK1/2 signaling-dependent manner. Furthermore, silencing of Rab32 in vivo suppressed tumor malignancy via ERK/Drp1 axis. Rab32 regulates ERK1/2/Drp1-dependent mitochondrial fission and causes mesenchymal transition, promoting migration and invasion of GBM. It serves as a novel therapeutic target for GBM, especially for the most malignant mesenchymal subtype. Schematic of Rab32 promotes GBM aggressiveness via regulation of ERK/Drp1-mediated mitochondrial fission. Rab32 transports Drp1 from the cytoplasm to the mitochondria and recruits ERK1/2 to activate the ser616 site of Drp1, which in turn mediates mitochondrial fission and promotes mesenchymal transition, migration and invasion of GBM.

Early DNase-I therapy delays secondary brain damage after traumatic brain injury in adult mice.

Traumatic brain injury (TBI) causes the release of danger-associated molecular patterns (DAMP) from damaged or dead cells, which contribute to secondary brain damage after TBI. Cell-free DNA (cfDNA) is a DAMP known to cause disruption of the blood-brain barrier (BBB), promote procoagulant processes, brain edema, and neuroinflammation. This study tested the hypothesis that administration of deoxyribonuclease-I (DNase-I) has a beneficial effect after TBI. Mice (n = 84) were subjected to controlled cortical impact (CCI) and posttraumatic intraperitoneal injections of low dose (LD) or high dose (HD) of DNase-I or vehicle solution at 30 min and 12 h after CCI. LD was most effective to reduce lesion volume (p = 0.003), brain water content (p < 0.0001) and to stabilize BBB integrity (p = 0.019) 1 day post-injury (dpi). At 6 h post injury LD-treated animals showed less cleavage of fibrin (p = 0.0014), and enhanced perfusion as assessed by micro-computer-tomography (p = 0.027). At 5 dpi the number of Iba1-positive cells (p = 0.037) were reduced, but the number of CD45-positive cells, motoric function and brain lesion volume was not different. Posttraumatic-treatment with DNase-I therefore stabilizes the BBB, reduces the formation of brain edema, immune response, and delays secondary brain damage. DNase-I might be a new approach to extend the treatment window after TBI.

Resolving the lineage relationship between malignant cells and vascular cells in glioblastomas.

Glioblastoma multiforme (GBM), a highly malignant and heterogeneous brain tumor, contains various types of tumor and non-tumor cells. Whether GBM cells can trans-differentiate into non-neural cell types, including mural cells or endothelial cells (ECs), to support tumor growth and invasion remains controversial. Here we generated two genetic GBM models de novo in immunocompetent mouse brains, mimicking essential pathological and molecular features of human GBMs. Lineage-tracing and transplantation studies demonstrated that, although blood vessels in GBM brains underwent drastic remodeling, evidence of trans-differentiation of GBM cells into vascular cells was barely detected. Intriguingly, GBM cells could promiscuously express markers for mural cells during gliomagenesis. Furthermore, single-cell RNA sequencing showed that patterns of copy number variations (CNVs) of mural cells and ECs were distinct from those of GBM cells, indicating discrete origins of GBM cells and vascular components. Importantly, single-cell CNV analysis of human GBM specimens also suggested that GBM cells and vascular cells are likely separate lineages. Rather than expansion owing to trans-differentiation, vascular cell expanded by proliferation during tumorigenesis. Therefore, cross-lineage trans-differentiation of GBM cells is very unlikely to occur during gliomagenesis. Our findings advance understanding of cell lineage dynamics during gliomagenesis, and have implications for targeted treatment of GBMs.

A diagnostic circulating miRNA signature as orchestrator of cell invasion via TKS4/TKS5/EFHD2 modulation in human gliomas.

BACKGROUND: Altered microRNA profiles have been observed not only in tumour tissues but also in biofluids, where they circulate in a stable form thus representing interesting biomarker candidates. This study aimed to identify a microRNA signature as a non-invasive biomarker and to investigate its impact on glioma biology. METHODS: MicroRNAs were selected using a global expression profile in preoperative serum samples from 37 glioma patients. Comparison between serum samples from age and gender-matched controls was performed by using the droplet digital PCR. The ROC curve and Kaplan-Meier survival analyses were used to evaluate the diagnostic/prognostic values. The functional role of the identified signature was assessed by gain/loss of function strategies in glioma cells. RESULTS: A three-microRNA signature (miR-1-3p/-26a-1-3p/-487b-3p) was differentially expressed in the serum of patients according to the isocitrate dehydrogenase (IDH) genes mutation status and correlated with both patient Overall and Progression Free Survival. The identified signature was also downregulated in the serum of patients compared to controls. Consistent with these results, the signature expression and release in the conditioned medium of glioma cells was lower in IDH-wild type cells compared to the mutated counterpart. Furthermore, in silico analysis of glioma datasets showed a consistent deregulation of the signature according to the IDH mutation status in glioma tumour tissues. Ectopic expression of the signature negatively affects several glioma functions. Notably, it impacts the glioma invasive phenotype by directly targeting the invadopodia-related proteins TKS4, TKS5 and EFHD2. CONCLUSIONS: We identified a three microRNA signature as a promising complementary or even an independent non-invasive diagnostic/prognostic biomarker. The signature displays oncosuppressive functions in glioma cells and impacts on proteins crucial for migration and invasion, providing potential targets for therapeutic intervention.

Effect of post-operative infections on glioblastoma outcomes.

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumour with a poor prognosis. The risk of developing a post-operative infection after craniotomy is the highest in GBM patients. Historical beliefs suggest that post-operative infections render a survival advantage in GBM patients, however recent clinical neurosurgical reports involving large multicentric patient cohorts do not support this claim. Nonetheless, the relationship has not been extensively studied which poses the need for further large, scaled studies to determine the association between post-operative infections and survival benefit in GBM patients.

Homotypic Membrane-Enhanced Blood-Brain Barrier Crossing and Glioblastoma Targeting for Precise Surgical Resection and Photothermal Therapy.

The crossing of blood-brain barrier (BBB) is essential for glioblastoma (GBM) therapy, and homotypic targeting is an effective strategy to achieve BBB crossing. In this work, GBM patient-derived tumor cell membrane (GBM-PDTCM) is prepared to cloak gold nanorods (AuNRs). Relying on the high homology of the GBM-PDTCM to the brain cell membrane, GBM-PDTCM@AuNRs realize efficient BBB crossing and selective GBM targeting. Meanwhile, owing to the functionalization of Raman reporter and lipophilic fluorophore, GBM-PDTCM@AuNRs are able to generate fluorescence and Raman signals at GBM lesion, and almost all tumor can be precisely resected in 15 min by the guidance of dual signals, ameliorating the surgical treatment for advanced GBM. In addition, photothermal therapy for orthotopic xenograft mice is accomplished by intravenous injection of GBM-PDTCM@AuNRs, doubling the median survival time of the mice, which improves the nonsurgical treatment for early GBM. Therefore, benefiting from homotypic membrane-enhanced BBB crossing and GBM targeting, all-stage GBM can be treated with GBM-PDTCM@AuNRs in distinct ways, providing an alternative idea for the therapy of tumor in the brain.

[LASER INTERSTITIAL THERMAL THERAPY (LITT) IN NEUROSURGERY].

INTRODUCTION: Laser interstitial thermal therapy (LITT) has emerged as a new treatment option for various conditions within the neurosurgery world, not only due to its minimal invasiveness but also because it has been shown to be safe and effective. Combined with magnetic resonance thermography, LITT gives surgeons the ability to estimate damage in real time and precisely ablate the target tissue while minimizing thermal damage to adjacent structures. In recent years, LITT has become a reality in epilepsy surgery and in neuro-oncology and is emerging as an option in other fields in neurosurgery.