Spiking GABAergic OPC tumor cells prolong survival in IDH1 mutant glioma

Prior studies have shown that glioma cells form synapses with neurons to receive synaptic inputs. To discern if glioma cells can send outgoing electrochemical signals in the form of action potentials (APs), we employed Patch-sequencing on surgically-resected human glioma slices. Results showed that half of patched cells in IDH1 mutant (IDH1mut) tumors demonstrate select properties of both neurons and glia and fire single, short APs. To define the transcriptional profiles of these hybrid cells (HCs) and discern if they are tumor derived, we developed a computational tool, Single Cell Rule Association Mining (SCRAM), to annotate features in each cell individually. SCRAM revealed that HCs represent a heterogenous group of tumor and non-tumor cells that are uniformly defined by both GABAergic neuron and oligodendrocyte precursor cell (GABA-OPC) transcriptional signatures. We found that GABA-OPC tumor cells express requisite voltage-gated ion channels needed to fire APs. We validated our findings in human single cell and bulk RNA-seq datasets, confirming that GABA-OPCs represent 40% of IDH1mut tumor cells, correlate with survival outcomes in IDH1mut human patients and are also found in select molecular subtypes of IDH1 wild-type tumors. These studies describe a new cell type in IDH1mut glioma with unique electrophysiological and transcriptomic properties.

Seizure outcomes after resection of primary brain tumors in pediatric patients: a systematic review and meta-analysis

PURPOSE

Primary brain neoplasms are the most common solid tumors in pediatric patients and seizures are a common presenting symptom. Surgical intervention improves oncologic outcomes and seizure burden. A better understanding of factors that influence seizure outcomes in the surgical management of primary brain tumors of childhood can guide treatment approach thereby improving patient quality of life.

METHODS

We performed a systematic analysis using articles queried from PubMed, EMBASE, and Cochrane published from January 1990 to August 2022 to determine predictors of seizure outcomes in pediatric patients undergoing resection of primary brain tumors.

RESULTS

We identified 24 retrospective cohort studies, one prospective cohort study, and one mixed retrospective and prospective study for the systematic analysis. A total of 831 pediatric patients were available for analysis. 668 (80.4%) patients achieved seizure freedom after surgery. Complete tumor resection increased the likelihood of a seizure-free (Engel I) outcome compared to subtotal resection (OR 7.1, 95% CI 2.3-21.9). Rates of Engel I seizure outcomes did not significantly differ based on factors such as age at seizure onset, duration of epilepsy, gender, tumor laterality, or age at surgery, but trended towards significance for improved outcomes in temporal lobe tumors.

CONCLUSION

Primary brain tumors in the pediatric population are commonly associated with seizures. Resection of these lesions reduces seizure burden and is associated with high rates of seizure freedom. Complete resection, compared to subtotal resection, significantly increases the likelihood of seizure-free outcomes.

Thoracolumbar Scoliosis in Pediatric Patients With Loeys-Dietz Syndrome: A Case Series

Background Loeys-Dietz syndrome (LDS) is a genetic connective tissue disorder that predominantly affects cardiovascular, skeletal, and craniofacial structures. Associated thoracolumbar scoliosis in LDS can be challenging to manage, though other etiologies of pediatric scoliosis have better-defined management guidelines. We examined our institutional experience regarding the treatment of pediatric patients with LDS and scoliosis. Methodology In this retrospective study, all patients seen at our pediatric tertiary care center from 2004 through 2018 with a diagnosis of LDS were reviewed, and those with radiographic diagnoses of scoliosis (full-length scoliosis X-rays) were included. Demographic, clinical, and radiographic parameters were collected, and management strategies were reported. Results A total of 39 LDS patients whose ages ranged between seven and 13 years were identified. A total of nine patients were radiographically diagnosed with scoliosis, but three patients were excluded due to incomplete medical records, leaving six patients. The median age at scoliosis diagnosis was 11.5 years, with a median follow-up of 51 months. Two patients were successfully managed with observation (average initial Cobb angle (CA): 14°, average final CA: 20.5°). Two were braced, one successfully (initial CA: 15°, final CA: 30°) and one with a progressive disease requiring surgery (initial CA: 40°, final CA: 58°). Of the two who were offered surgical correction, one underwent surgery with a durable correction of spinal deformity (CA: 33° to 19°). One patient underwent a recent correction of aortic root dilatation and was not a candidate for scoliosis surgery. Conclusions Principles of adolescent idiopathic scoliosis management such as bracing for CA of 20-50° and surgery for CA of >50° can be applied to LDS patients with good outcomes. This augments our understanding of the treatment algorithm for pediatric patients with LDS.

Varied histomorphology and clinical outcomes of FGFR3-TACC3 fusion gliomas

Targeted therapies for driver gene fusions in cancers have yielded substantial improvements in care. Here, the authors outline a case series of 6 patients with FGFR3-TACC3 fusion in primary brain tumors ranging from polymorphous low-grade neuroepithelial tumor of the young to papillary glioneuronal tumors and glioblastoma (GBM). Previous studies indicated the FGFR3-TACC3 fusion provides survival benefit to GBM patients. Consistent with this, 2 patients with GBM had unexpectedly good outcomes and survived for 5 and 7 years, respectively. In contrast, 2 patients with initially lower graded tumors survived only 3 years and 1 year, respectively. One patient received erdafitinib, a targeted FGFR inhibitor, for 3 months at late disease recurrence and no response was seen. There were varied histomorphological features, including many cases that lacked the characteristic FGFR3-TACC3 pathology. The findings of this cohort suggest that molecular testing is justified, even for glioma cases lacking classic histopathological signatures. Currently, FGFR3-TACC3 fusion gliomas are often classified on the basis of histopathological features. However, further research is needed to examine whether IDH1/2-wild-type tumors with FGFR3-TACC3 fusion should be classified as a subtype on the basis of this molecular fusion. Because patients with IDH1/2-wild-type GBM with FGFR3-TACC3 fusion have improved survival, routine molecular testing for this mutation in patients enrolled in clinical trials and subsequent stratification may be warranted.

DDEL-06. HEAT-ACTIVATED DOXORUBICIN UPTAKE FACILITATED BY LASER INTERSTITIAL THERMAL THERAPY

Although surgery has been shown to provide a survival benefit in patients with glioblastoma multiforme (GBM), tumor location and geometry may restrict maximal resection. Additionally, the margin of resection cavity contains infiltrating tumor cells that result in recurrence and therapy resistance. Laser interstitial thermal therapy (LITT) is a treatment modality that uses thermal energy to destroy tumor cells. LITT is useful for tumors that are not appropriate for conventional surgical resection. Our laboratory has developed a LITT model to study LITT in a genetically engineered mouse model of GBM. The combination of heat activated nanoparticles and LITT represents an opportunity to target the infiltrating tumor margin, extending the treatment penumbra. We hypothesized that heat-activated liposomes containing doxorubicin (ThermoDox, Celsion) would demonstrate infiltration into the brain parenchyma after treatment with LITT. We treated tumor-bearing mice with LITT or sham (laser fiber implanted but not activated) after either ThermoDox (5mg/kg) or PBS infusion, 30 minutes before performing LITT or sham treatment. We euthanized these mice 1 hour after LITT or sham treatment, harvested brains, and performed immunofluorescence to identify doxorubicin in parenchymal cells. Doxorubicin was identified in 100% of mice treated with LITT following ThermoDox administration which is in contrast with groups treated with LITT and PBS, sham and ThermoDox, and sham and PBS. Here, we show that heat-activated nanoparticles are disrupted through hyperthermia followed by the release of doxorubicin only in the presence of hyperthermia, which paves way for the clinical use of ThermoDox as adjunct chemotherapy following LITT in treatment-resistant GBM treatment.

Comparative study of preoperative functional imaging combined with tractography for prediction of iatrogenic motor deficits

OBJECTIVE

Robust preoperative imaging can improve the extent of resection in patients with brain tumors while minimizing postoperative neurological morbidity. Both structural and functional imaging techniques can provide helpful preoperative information. A recent study found that transcranial magnetic stimulation (TMS) tractography has significant predictive value for permanent deficits. The present study directly compares the predictive value of TMS tractography and task-based functional MRI (fMRI) tractography in the same cohort of glioma patients.

METHODS

Clinical outcome data were collected from charts of patients with motor eloquent glioma and preoperative fMRI and TMS studies. The primary outcome was a new or worsened motor deficit present at the 3-month postoperative follow-up, which was termed a "permanent deficit." Postoperative MR images were overlaid onto preoperative plans to determine which imaging features were resected. Multiple fractional anisotropic thresholds (FATs) were screened for both TMS and fMRI tractography. The predictive value of the various thresholds was modeled using receiver operating characteristic curve analysis.

RESULTS

Forty patients were included in this study. Six patients (15%) sustained permanent postoperative motor deficits. A significantly greater predictive value was found for TMS tractography than for fMRI tractography regardless of the FAT. Despite 35% of patients showing clinically relevant neuroplasticity captured by TMS, only 2.5% of patients showed a blood oxygen level–dependent signal displaced from the precentral gyrus. Comparing the best-performing FAT for both modalities, TMS seeded tractography showed superior predictive value across all metrics: sensitivity, specificity, positive predictive value, and negative predictive value.

CONCLUSIONS

The results from this study indicate that the prediction of permanent deficits with TMS tractography is superior to that with fMRI tractography, possibly because TMS tractography captures clinically relevant neuroplasticity. However, future large-scale prospective studies are needed to fully illuminate the proper role of each modality in comprehensive presurgical workups for patients with motor-eloquent tumors.

Myeloid sarcoma of the skull base: A case report and systematic literature review

Background:

Myeloid sarcoma (MS), or chloroma, is a rare extramedullary malignant tumor that consists of undifferentiated granulocytic cells, and it is most commonly associated with acute myeloid leukemia (AML). Intracranial MS accounts for 0.4% of MS cases, and involvement of the skull base and visual dysfunction is rarely reported. However, the optimal treatment and response to treatment of skull base MS in the presence of visual symptoms is unknown.

Case Description:

A 30-year-old male with a history of AML presented with rapidly progressive vision loss and a sellar and parasellar mass with bilateral cavernous sinus and optic nerve encasement. The patient underwent endoscopic endonasal transsphenoidal biopsy revealing intracranial MS. He was treated postoperatively with high-dose intravenous and intrathecal cytarabine and had complete restoration of his vision by postoperative day 11. A systematic review of the literature identified six cases of skull base MS, five of whom presenting with visual symptoms. All patients underwent systemic chemotherapy with cytarabine and/or cyclophosphamide, with infrequent use of intrathecal chemotherapy or radiation. Those with reported visual outcomes were diagnosed 4 months or longer after symptom onset and demonstrated no visual improvement with treatment.

Conclusion:

Skull base MS is a rare disease entity with a high prevalence of visual dysfunction. Our patient’s complete disappearance of intracranial disease and resolution of visual symptoms with systemic and intrathecal chemotherapy highlight the importance of timely diagnosis and appropriate treatment without a need for direct surgical decompression.

Biologic Therapies for the Management of Cutaneous Findings in Genodermatoses: A Review

Genodermatoses are genetically inherited dermatologic conditions. The management of cutaneous findings in genodermatoses is challenging, and first-line therapies, such as steroids and/or retinoids, are often inadequate. In recent years, research on the molecular basis of genodermatoses has led to the use of biologic therapies for intractable disease. Here, we review the evidence regarding the use of available biologic therapies for the management of dermatologic findings in genodermatoses. Biologic therapies appear to be promising therapeutic options for several recalcitrant genodermatoses, especially those with underlying immune dysregulation. However, not all genodermatoses are amenable to biologic therapies, and some have been shown to paradoxically worsen under treatment. Biologic therapies offer a novel avenue to target refractory genodermatoses. However, evidence supporting the use of biologic therapies in the management of genodermatoses is mostly limited to case reports and case series. Further studies are warranted to determine the safety and efficacy of biologic therapies for the management of cutaneous findings in genodermatoses.