Early rhombic lip Protogenin+ve stem cells in a human-specific neurovascular niche initiate and maintain group 3 medulloblastoma.

We identify a population of Protogenin-positive (PRTG+ve) MYChigh NESTINlow stem cells in the four-week-old human embryonic hindbrain that subsequently localizes to the ventricular zone of the rhombic lip (RLVZ). Oncogenic transformation of early Prtg+ve rhombic lip stem cells initiates group 3 medulloblastoma (Gr3-MB)-like tumors. PRTG+ve stem cells grow adjacent to a human-specific interposed vascular plexus in the RLVZ, a phenotype that is recapitulated in Gr3-MB but not in other types of medulloblastoma. Co-culture of Gr3-MB with endothelial cells promotes tumor stem cell growth, with the endothelial cells adopting an immature phenotype. Targeting the PRTGhigh compartment of Gr3-MB in vivo using either the diphtheria toxin system or chimeric antigen receptor T cells constitutes effective therapy. Human Gr3-MBs likely arise from early embryonic RLVZ PRTG+ve stem cells inhabiting a specific perivascular niche. Targeting the PRTGhigh compartment and/or the perivascular niche represents an approach to treat children with Gr3-MB.

Failure of human rhombic lip differentiation underlies medulloblastoma formation.

Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain1-4. Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage5-8. By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL9,10. However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage3,4. Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental time. Knockdown of OTX2 in model systems relieves this differentiation blockade, which allows MB cells to spontaneously proceed along normal developmental differentiation trajectories. The specific nature of the split human RL, which is destined to generate most of the neurons in the human brain, and its high level of susceptible EOMES+KI67+ unipolar brush cell progenitor cells probably predisposes our species to the development of G4 MB.

Recent advances in the molecular understanding of medulloblastoma.

Medulloblastoma is the most common pediatric malignant brain tumor composed of four molecular subgroups. Recent intensive genomics has greatly contributed to our understanding of medulloblastoma pathogenesis. Sequencing studies identified novel mutations involved in the cyclic AMP-dependent pathway or RNA processing in the Sonic Hedgehog (SHH) subgroup, and core-binding factor subunit alpha (CBFA) complex in the group 4 subgroup. Likewise, single-cell sequencing provided detailed insights into the cell of origin associated with brain development. In this review, we will summarize recent findings by sequencing analyses for medulloblastoma.

Long-Term Effects on Preventing Stroke after Endovascular Treatment or Bypass Surgery for Intracranial Arterial Stenosis.

BACKGROUND: Intracranial arterial stenosis (ICAS) is an important cause of ischemic stroke worldwide due to its higher risk of recurrence with medical therapy. Although some large randomized studies failed to show the superiority of surgical treatment compared with medical therapy, the results of medical therapy are not sufficient. There are patients who still benefit from surgical treatment. This retrospective analysis aimed to evaluate the long-term efficacy of surgical therapy with percutaneous transluminal angioplasty and/or stenting (PTA/PTAS) or extracranial-intracranial (EC/IC) bypass surgery for patients with ICAS. METHODS: Between October 2005 and December 2016, 55 ICAS patients were treated with PTA/PTAS or EC-IC bypass surgery. Their electronic medical records were retrospectively reviewed and analyzed. The primary outcome was all adverse events beyond 30 days after a revascularization procedure. RESULTS: We performed 21 cases (35%) of PTA, 4 cases (7%) of PTAS, and 34 cases (58%) of EC-IC bypass surgery and the median follow-up duration was 66 months (range 1-144 months). The occurrence rate of the primary outcome was 10.2% and only 1 patient (1.8%) experienced ipsilateral disabling ischemic stroke beyond 30 days. The long-term functional independent survival rate was 83.6%. CONCLUSIONS: We demonstrated a long-term favorable outcome of combined surgical intervention for ICAS patients with PTA/PTAS and EC-IC bypass surgery, and the result was better than previously reported outcomes of medical therapy. Additional multicenter studies are required to draw firm conclusions on the efficacy of reduction of recurrent stroke in patients with ICAS.

Development of a rapid and comprehensive genomic profiling test supporting diagnosis and research for gliomas.

A prompt and reliable molecular diagnosis for brain tumors has become crucial in precision medicine. While Comprehensive Genomic Profiling (CGP) has become feasible, there remains room for enhancement in brain tumor diagnosis due to the partial lack of essential genes and limitations in broad copy number analysis. In addition, the long turnaround time of commercially available CGPs poses an additional obstacle to the timely implementation of results in clinics. To address these challenges, we developed a CGP encompassing 113 genes, genome-wide copy number changes, and MGMT promoter methylation. Our CGP incorporates not only diagnostic genes but also supplementary genes valuable for research. Our CGP enables us to simultaneous identification of mutations, gene fusions, focal and broad copy number alterations, and MGMT promoter methylation status, with results delivered within a minimum of 4 days. Validation of our CGP, through comparisons with whole-genome sequencing, RNA sequencing, and pyrosequencing, has certified its accuracy and reliability. We applied our CGP for 23 consecutive cases of intracranial mass lesions, which demonstrated its efficacy in aiding diagnosis and prognostication. Our CGP offers a comprehensive and rapid molecular profiling for gliomas, which could potentially apply to clinical practices and research primarily in the field of brain tumors.

Genotype-relevant neuroimaging features in low-grade epilepsy-associated tumors.

Introduction: Low-grade epilepsy-associated tumors are the second most common histopathological diagnoses in cases of drug-resistant focal epilepsy. However, the connection between neuroimaging features and genetic alterations in these tumors is unclear, prompting an investigation into genotype-relevant neuroimaging characteristics. Methods: This study retrospectively analyzed neuroimaging and surgical specimens from 46 epilepsy patients with low-grade epilepsy-associated neuroepithelial tumors that had genetic mutations identified through panel sequencing to investigate their relationship to genotypes. Results: Three distinct neuroimaging groups were established: Group 1 had indistinct borders and iso T1-weighted and slightly high or high T2-weighted signal intensities without a diffuse mass effect, associated with 93.8% sensitivity and 100% specificity to BRAF V600E mutations; Group 2 exhibited sharp borders and very or slightly low T1-weighted and very high T2-weighted signal intensities with a diffuse mass effect and 100% sensitivity and specificity for FGFR1 mutations; and Group 3 displayed various characteristics. Histopathological diagnoses including diffuse low-grade glioma and ganglioglioma showed no clear association with genotypes. Notably, postoperative seizure-free rates were higher in Group 1 tumors (BRAF V600E) than in Group 2 tumors (FGFR1). Discussion: These findings suggest that tumor genotype may be predicted by neuroimaging before surgery, providing insights for personalized treatment approaches.

Efficacy and safety of bevacizumab, irinotecan, and temozolomide combination for relapsed or refractory pediatric central nervous system embryonal tumor: a single-institution study.

OBJECTIVE: This study aimed to evaluate the efficacy and safety of combination therapy with bevacizumab (Bev), irinotecan (CPT-11), and temozolomide (TMZ) in children with central nervous system (CNS) embryonal tumor relapse. METHODS: The authors retrospectively examined 13 consecutive pediatric patients with relapsed or refractory CNS embryonal tumors who received combination therapy comprising Bev, CPT-11, and TMZ. Specifically, 9 patients had medulloblastoma, 3 had atypical teratoid/rhabdoid tumor (AT/RT), and 1 had CNS embryonal tumor with rhabdoid features. Of the 9 medulloblastoma cases, 2 were categorized in the Sonic hedgehog subgroup and 6 in molecular subgroup 3 for medulloblastoma. RESULTS: The complete and partial objective response rates were 66.6% in patients with medulloblastoma and 75.0% in patients with AT/RT or CNS embryonal tumors with rhabdoid features. Furthermore, the 12- and 24-month progression-free survival rates were 69.2% and 51.9% for all patients with recurrent or refractory CNS embryonal tumors, respectively. In contrast, the 12- and 24-month overall survival rates were 67.1% and 58.7%, respectively, for all patients with relapsed or refractory CNS embryonal tumors. The authors observed grade 3 neutropenia, thrombocytopenia, proteinuria, hypertension, diarrhea, and constipation in 23.1%, 7.7%, 23.1%, 7.7%, 7.7%, and 7.7% of patients, respectively. Furthermore, grade 4 neutropenia was observed in 7.1% of patients. Nonhematological adverse effects, such as nausea and constipation, were mild and controlled with standard antiemetics. CONCLUSIONS: This study demonstrated favorable survival outcomes in patients with relapsed or refractory pediatric CNS embryonal tumors and thus helped to investigate the efficacy of combination therapy comprising Bev, CPT-11, and TMZ. Moreover, combination chemotherapy had high objective response rates, and all adverse events were tolerable. To date, data supporting the efficacy and safety of this regimen in the relapsed or refractory AT/RT population are limited. These findings suggest the potential efficacy and safety of combination chemotherapy in patients with relapsed or refractory pediatric CNS embryonal tumors.

Acute Hydrocephalus Requiring External Ventricular Drainage Following Perimesencephalic Nonaneurysmal Subarachnoid Hemorrhage in a Pediatric Patient: Case Report and Review of the Literature.

BACKGROUND: Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a well-described subset of subarachnoid hemorrhage with an excellent prognosis in adults. However, its characteristics in the pediatric population have not yet been fully understood. We present a case of acute hydrocephalus requiring external ventricular drainage following pediatric PNSAH. CASE DESCRIPTION: A previously healthy 10-year-old girl was admitted to our neurosurgical department after sudden onset of severe headache with vomiting during exercise. Cerebral non-contrast computed tomography detected subarachnoid hemorrhage filling all perimesencephalic cisterns. However, digital subtraction angiography could not locate the hemorrhage source. Her consciousness deteriorated within 7 hours of onset, and a computed tomography scan revealed acute hydrocephalus. We subjected the patient to external ventricular drainage for 10 days. She was discharged after 38 days of hospitalization, when she was physically and neuropsychologically healthy. Repeated digital subtraction angiography performed at the 6-month follow-up did not show any obvious source of hemorrhage except for a variant drainage pattern of the basal vein of Rosenthal. Based on the observations, we diagnosed the patient with PNSAH of a venous origin. CONCLUSIONS: We propose that acute hydrocephalus be suspected in pediatric patients with nonaneurysmal subarachnoid hemorrhage filling all perimesencephalic cisterns, as in adults. We also propose that one of the possible causes of pediatric PNSAH as of venous origin and related to the abnormal drainage pattern of basal vein of Rosenthal and elevation of venous pressure with exercise. Immediate surgical drainage could obtain a good outcome in a symptomatic case.

Tumor Volume Decrease via Feeder Occlusion for Treating a Large, Firm Trigone Meningioma.

Trigone meningiomas are considered a surgical challenge, as they tend to be considerably large and hypervascularized at the time of presentation. We experienced a case of a large and very hard trigone meningioma that was effectively treated using initial microsurgical feeder occlusion followed by surgery in stages. A 19-year-old woman who presented with loss of consciousness was referred to our hospital for surgical treatment of a brain tumor. Radiological findings were compatible with a left ventricular trigone meningioma extending laterally in proximity to the Sylvian fissure. At initial surgery using the transsylvian approach, main feeders originating from the anterior and lateral posterior choroidal arteries were occluded at the inferior horn; however, only a small section of the tumor could initially be removed because of its firmness. Over time, feeder occlusion resulted in tumor necrosis and a 20% decrease in its diameter; the mass effect was alleviated within 1 year. The residual meningioma was then totally excised in staged surgical procedures after resection became more feasible owing to ischemia-induced partial softening of the tumor. When a trigone meningioma is large and very hard, initial microsurgical feeder occlusion in the inferior horn can be a safe and effective option, and can lead to necrosis, volume decrease, and partial softening of the residual tumor to allow for its staged surgical excision.

Effect of Stress-free Therapy on Cerebral Blood Flow: Comparisons among patients with metabolic cardiovascular disease, healthy subjects and placebo-treated subjects.

BACKGROUND AND AIMS: We have developed a Stress-free Therapy(®) device wherein "Pinpoint Plantar Long-wavelength Infrared Light Irradiation (PP-LILI)" increases peripheral-deep body temperature and blood flow volume and stabilizes blood pressure as well as significantly reduces stress hormones such as adrenocorticotrophic hormone and cortisol without using drugs. Moreover, we have found this therapy to significantly improve blood glucose and insulin resistance in patients with type 2 diabetes. Based on this background of clinical efficacy, we validated changes in cerebral blood flow in patients with metabolic cardiovascular disease and examined the efficacy of Stress-free Therapy(®) on cerebral blood flow as compared to that in healthy control subjects and placebo-treated patients. RESULTS: The change in cerebral blood flow volume during 15-minute PP-LILI was 5.1 ± 1.8 mL/min in patients with metabolic cardiovascular disease, showing a significant increase (P<0.05) of 3.1 mL/min as compared with the mean blood flow value after resting for 15 minutes. CONCLUSIONS: Our results suggested Stress-free Therapy(®) to significantly increase cerebral blood flow, possibly leading to the prevention of metabolic cardiovascular disease.