Lack of SMARCB1 expression characterizes a subset of human and murine peripheral T-cell lymphomas.

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is a heterogeneous group of malignancies with poor outcome. Here, we identify a subgroup, PTCL-NOSSMARCB1-, which is characterized by the lack of the SMARCB1 protein and occurs more frequently in young patients. Human and murine PTCL-NOSSMARCB1- show similar DNA methylation profiles, with hypermethylation of T-cell-related genes and hypomethylation of genes involved in myeloid development. Single-cell analyses of human and murine tumors revealed a rich and complex network of interactions between tumor cells and an immunosuppressive and exhausted tumor microenvironment (TME). In a drug screen, we identified histone deacetylase inhibitors (HDACi) as a class of drugs effective against PTCL-NOSSmarcb1-. In vivo treatment of mouse tumors with SAHA, a pan-HDACi, triggered remodeling of the TME, promoting replenishment of lymphoid compartments and reversal of the exhaustion phenotype. These results provide a rationale for further exploration of HDACi combination therapies targeting PTCL-NOSSMARCB1- within the TME.

Developmental and epileptic encephalopathies after successful treatment of pediatric ALL: A case series and review of literature.

Successful treatment of acute lymphoblastic leukemia (ALL) requires multiagent chemotherapy regimens and central nervous system prophylaxis, including intrathecal methotrexate. Although acute symptomatic seizures can occur during ALL treatment, epilepsy is less common. Furthermore, drug resistant epilepsy (DRE) is rare, presenting with two phenotypes: focal epilepsy, such as temporal lobe, or epileptic encephalopathies (EE), such as Lennox-Gastaut syndrome (LGS). For ALL survivors, the development of DRE has significant impact on morbidity, mortality, and quality of life. We describe four patients with ALL remission, who developed EEs, of which 3 had LGS. Mean age at ALL diagnosis was 1.9 years; range 1.1-2.5 years. All, but one, had normal development prior to ALL. No patient had CNS leukemic involvement. All patients received CNS prophylaxis with intrathecal methotrexate, without cranial radiotherapy. Three had symptomatic methotrexate neurotoxicity during treatment. The mean age at first seizure was 5.6 years; range 3.9-7.5 years, with a mean latency of 3.7 years from ALL diagnosis. All patients developed drug resistant EEs, moderate intellectual disability, and neuropsychiatric co-morbidities. Two patients had a minimal response to corpus callosotomy (CC), and one did not respond the ketogenic diet. Successful treatment of childhood ALL is rarely associated with the development of DRE and EEs. Young age at ALL diagnosis (<3 years) may be a predisposing factor. Palliative treatments, including ketogenic diet and CC have limited benefit in these patients. Individual genetic susceptibility to MTX toxicity is likely related to epileptogenesis, and further research is required for epilepsy biomarkers.

Canadian Consensus for Treatment of BRAF V600E Mutated Pediatric and AYA Gliomas.

Background: The treatment of BRAF V600E gliomas with BRAF inhibitors (BRAFis) and MEK inhibitors (MEKis) has been increasingly integrated into clinical practice for pediatric low-grade gliomas (PLGGs) and pediatric high-grade gliomas (HGGs). However, some questions remain unanswered, such as the best time to start targeted therapy, duration of treatment, and discontinuation of therapy. Given that no clinical trial has been able to address these critical questions, we developed a Canadian Consensus statement for the treatment of BRAF V600E mutated pediatric as well as adolescent and young adult (AYA) gliomas. Methods: Canadian neuro-oncologists were invited to participate in the development of this consensus. The consensus was discussed during monthly web-based national meetings, and the algorithms were revised until a consensus was achieved. Results: A total of 26 participants were involved in the development of the algorithms. Two treatment algorithms are proposed, one for the initiation of treatment and one for the discontinuation of treatment. We suggest that most patients with BRAF V600E gliomas should be treated with BRAFis ± MEKis upfront. Discontinuation of treatment can be considered in certain circumstances, and we suggest a slow wean. Conclusions: Based on expert consensus in Canada, we developed algorithms for treatment initiation of children and AYA with BRAF V600E gliomas as well as a discontinuation algorithm.

Physician, patient, and caregiver support for a formal certification in pediatric neuro-oncology: A survey-based report from the SNO pediatrics working group.

Background: Although CNS tumors are the most common pediatric cancer in the United States, most physicians caring for these patients are not formally certified in the subspecialty. To determine support for developing a formal certification process in pediatric neuro-oncology, the Society for Neuro-Oncology's Pediatrics Special Interest Track Training and Credentialing working group performed a cross-sectional survey-based study of physicians and patients/caregivers of children with a CNS tumor history. Methods: Surveys were built in Survey Monkey and were available for 3 months. The physician survey had 34 questions and was open to doctors currently caring for pediatric neuro-oncology patients. The patient/caregiver survey had 13 questions. Both surveys were completed anonymously. Results: The physician survey was completed by 193 participants, the majority of whom self-identified as oncologists. Only 5.6% of survey participants had ever been board-certified in neuro-oncology; the majority of participating physicians were either unaware that this certification existed or thought they were not eligible due to training in pediatrics rather than neurology or internal medicine. Almost half of the self-identified pediatric neuro-oncologists had not completed any specific clinical neuro-oncology training. Over 75% of physicians were supportive of the implementation of a formal certification process in pediatric neuro-oncology. A total of 30 participants completed the patient/caregiver survey. Although the majority of survey participants were highly satisfied with their oncologist, 70% would have been more comfortable if their oncologist had been specifically certified in pediatric neuro-oncology. Conclusions: There is support from physicians, patients, and caregivers to establish a formal certification process in pediatric neuro-oncology.

Real-world experience of tyrosine kinase inhibitors in children, adolescents and adults with relapsed or refractory bone tumours: A Canadian Sarcoma Research and Clinical Collaboration (CanSaRCC) study.

OBJECTIVES: We conducted a retrospective multi-centre study to assess the real-world outcome of regorafenib (REGO) and cabozantinib (CABO) in recurrent/refractory bone tumours (BTs) including osteosarcoma (OST), Ewing sarcoma (EWS) and chondrosarcoma (CS)/extra-skeletal mesenchymal CS (ESMC). METHODS: After regulatory approval, data from patients with recurrent BT (11 institutions) were extracted from CanSaRCC (Canadian Sarcoma Research and Clinical Collaboration) database. Patient characteristics, treatment and outcomes were collected. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. RESULTS: From July 2018 to May 2022, 66 patients received REGO or CABO; 39 OST, 18 EWS, 4 CS and 5 ESMC. Median age was 27.8 years (range 12-76); median starting dose was 60 mg for CABO (n = 37, range 40-60) and 120 mg for REGO (n = 29, range 40-160). Twenty-eight (42.4%) patients required dose reduction: hand-foot syndrome 7 (10.6%), nausea/vomiting 1 (1.5%), diarrhoea 1 (1.5%), 2 elevated LFTs (3%), elevated bilirubin 1 (1.5%) and mucositis 1 (1.5%). The median OS for patients with OST, EWS, CS and ESMC was 8.5 months (n = 39, 95% CI 7-13.1); 13.4 months (n = 18, 95% CI 3.4-27.2), 8.1 (n = 4, 95% CI 4.1-9.3) and 18.2 (n = 5, 95% CI (10.4-na), respectively. Median PFS for OST, EWS, CS and ECMS was 3.5 (n = 39, 95% CI 2.8-5), 3.9 (n = 18, 95% CI 2.1-5.9), 5.53 (n = 4. 95% CI 2.13-NA) and 11.4 (n = 5, 95% CI 1.83-14.7), respectively. Age, line of therapy, REGO versus CABO, or time from diagnosis to initiation of TKI were not associated with PFS on univariable analysis. CONCLUSION: Our real-world data show that TKIs have meaningful activity in recurrent BT with acceptable toxicities when started at modified dosing. Inclusion of TKIs in earlier lines of treatment and/or maintenance therapy could be questions for future research.

Outcomes of a radiation sparing approach in medulloblastoma by subgroup in young children: an institutional review.

OBJECTIVE: To describe disease outcomes including overall survival and relapse patterns by subgroup in young pediatric patients treated for medulloblastoma with a radiation-sparing approach. METHODS: Retrospective analysis of clinical outcomes includes treatment, relapse, and salvage therapy and late effects in children treated for medulloblastoma with a radiation-sparing approach at British Columbia Children's Hospital (BCCH) between 2000 and 2020. RESULTS: There were 30 patients (median age 2.8 years, 60% male) treated for medulloblastoma with a radiation-sparing approach at BCCH. Subgroups included Sonic Hedgehog (SHH) (n = 14), group 3 (n = 7), group 4 (n = 6), and indeterminate status (n = 3). Three- and 5-year event-free survival (EFS) were 49.0% (30.2-65.4%) and 42.0% (24.2-58.9%) and overall survival (OS) 66.0% (95% CI 46.0-80.1%) and 62.5% (95% CI 42.5 and 77.2%), respectively, with a median follow-up of 9.5 years. Relapse occurred in 12/25 patients following a complete response, of whom six (group 4: n = 4; group 3: n = 1; unknown: n = 1) were successfully salvaged with craniospinal axis (CSA) RT and remain alive at a median follow-up of 7 years. Disease/treatment-related morbidity included endocrinopathies (n = 8), hearing loss n = 16), and neurocognitive abnormalities (n = 9). CONCLUSIONS: This radiation sparing treatment approach for young patients with medulloblastoma resulted in a durable cure in most patients with SHH subgroup medulloblastoma. In those patients with groups 3 and 4 medulloblastoma, relapse rates were high; however, most group 4 patients were salvaged with RT.

Neuroimaging to diagnose central nervous system tumours in children.

QUESTION: Headache, vomiting, lethargy, and seizures are common symptoms in healthy children with benign viral illnesses, but they are also signs that could represent a central nervous system (CNS) tumour. Primary care providers and guardians are hesitant to expose children to radiation associated with computed tomography scans or take on risks associated with the sedation frequently needed for magnetic resonance imaging. When should primary care providers order radiologic head imaging for children with common symptoms to identify those with a CNS tumour? ANSWER: Central nervous system tumours have no pathognomonic features, which often results in delays in diagnosis. Owing to the high prevalence of infratentorial tumours, children commonly present with symptoms of increased intracranial pressure, making a detailed history and a comprehensive physical examination, including ophthalmoscopy for papilledema, especially important. Magnetic resonance imaging is the criterion standard test but it may take time to access, and young children may need sedation. Hence, computed tomography may be a preferable first option.The HeadSmart initiative in the United Kingdom provides guidance to obtain brain imaging within 4 weeks of onset of persistent symptoms that are associated with CNS tumours. We advocate applying the same criteria in Canada in order to reduce delay in diagnosis of CNS tumours in children.

Retrospective dataset and survey analyses identify gaps in data collection for craniopharyngioma and priorities of patients and families affected by the disease.

INTRODUCTION: Craniopharyngioma is a rare, low-grade tumor located in the suprasellar region of the brain, near critical structures like the pituitary gland. Here, we concurrently investigate the status of clinical and genomic data in a retrospective craniopharyngioma cohort and survey-based data to better understand patient-relevant outcomes associated with existing therapies and provide a foundation to inform new treatment strategies. METHODS: Clinical, genomic, and outcome data for a retrospective cohort of patients with craniopharyngioma were collected and reviewed through the Children's Brain Tumor Network (CBTN) database. An anonymous survey was distributed to patients and families with a diagnosis of craniopharyngioma to understand their experiences throughout diagnosis and treatment. RESULTS: The CBTN repository revealed a large proportion of patients (40 - 70%) with specimens that are available for sequencing but lacked relevant quality of life (QoL) and functional outcomes. Frequencies of reported patient comorbidities ranged from 20-35%, which is significantly lower than historically reported. Survey results from 159 patients/families identified differences in treatment considerations at time of diagnosis versus time of recurrence. In retrospective review, patients and families identified preference for therapy that would improve QoL, rather than decrease risk of recurrence (mean 3.9 vs. 4.4 of 5) and identified endocrine issues as having the greatest impact on patients' lives. CONCLUSIONS: This work highlights the importance of prospective collection of QoL and functional metrics alongside robust clinical and molecular correlates in individuals with craniopharyngioma. Such comprehensive measures will facilitate biologically relevant therapeutic strategies that also prioritize patient needs.

Impact of Time to Diagnosis on Morbidity and Survival in Children With Malignant Central Nervous System Tumors.

OBJECTIVE: The aim was to determine the impact of time to diagnosis (TTD) on morbidity and mortality and to identify factors associated with overall survival (OS) in pediatric patients with malignant central nervous system (CNS) tumors. METHODS: This is a retrospective review of all malignant CNS tumors presenting to 2 tertiary care pediatric hospitals from 2000 to 2019. Cox proportional hazard model analysis outcomes included TTD and OS as well as morbidity; stratified by tumor category, age, relapse, and presence of metastatic disease. RESULTS: There were 197 children with malignant CNS tumors (mean age 8.7 y, 61% male). Tumors included medulloblastoma (N=58, 29.4%), ependymoma (N=27, 13.7%), high-grade glioma (N=42, 21.3%), germ cell tumors (N=47, 23.9%), and other embryonal tumors (N=23, 11.7%). Median TTD from symptom onset was 62 (interquartile range: 26.5 to 237.5 d) and 28% had metastatic disease. Three-year progression free survival was 55% and 3-year OS was 73.1%. Increased OS was associated with increased TTD (parameter estimate 0.12; confidence interval [CI]: 0.019-7.06; P =0.019), high-grade glioma (hazard ratio [HR]: 2.46; CI [1.03-5.86]; P =0.042), other embryonal tumor (HR: 2.84; CI [1.06-7.56]; P =0.037), relapse (HR: 10.14; CI: 4.52-22.70; P <0.001) and metastatic disease (HR: 3.25; CI: 1.51-6.96; P =0.002). Vision change (HR: 0.58; CI: 0.313-1.06; P =0.078), hearing loss (HR: 0.71; CI: 0.35-1.42; P =0.355), and cognitive impairment (HR: 0.73; CI: 0.45-1.19; P =0.205) were not associated with TTD in this model. CONCLUSIONS: Increased median TTD is associated with higher OS in pediatric patients treated for malignant CNS tumors. Tumor biology and treatment modality are more important factors than TTD for predicting morbidity and long-term outcomes in pediatric patients with CNS tumors.

An international study evaluating the epidemiology of intracranial germ cell tumors in the native versus immigrant Japanese populations: the need for an international registry.

BACKGROUND: Pediatric intra-cranial germ cell tumors (iGCTs) occur at an incidence of 0.6-1.2 cases/million/year in Western countries. The incidence is reported up to 5 times higher in Japan. It is unknown whether this increased incidence is due to genetic predisposition or environment. METHODS: The incidence of iGCTs in children ages 0-19 years was evaluated from December 1st, 1996-December 1st, 2016 in stable Japanese immigrant populations living abroad and compared to current native Japanese registry data. The incidence of medullobblastoma was used as a control to account for assumptions in the data. Sites were identified based on historical and population data of known large scale emigration from Japan during a period of industrialization from 1868-1912 which resulted in large, stable Japanese immigrant populations abroad. These three representative sites included Lima, Peru, San Paolo, Brazil, and Vancouver, Canada. Data was collected from registry and hospital-based resources within each region. RESULTS: A review of the Brain Tumor Registry of Japan from 1984-2004 revealed an incidence of 2.5 cases/million/year, lower than previously reported, and a lower incidence of medulloblastoma at 1.2 cases/million/year. Data from Vancouver, Canada, Lima, Peru, and San Paolo, Brazil included a total population of 731,174 Japanese persons. The ratio of all medulloblastoma to iGCT cases in Japan was identified as 1:2 while the ratio was 2:1, 6.5:1, and 5:1, respectively, in the other three locations. The data suggests increased incidence in native Japan may not translate to higher incidence in immigrant Japanese populations abroad and a clear genetic component was not found in our data set. CONCLUSIONS: A more precise and comprehensive study is needed to determine the cause of this difference in incidence. This study also emphasizes the importance of national and state registries and is a call to collaborate on state and country level epidemiology studies.

Human complete NFAT1 deficiency causes a triad of joint contractures, osteochondromas, and B-cell malignancy.

The discovery of humans with monogenic disorders has a rich history of generating new insights into biology. Here we report the first human identified with complete deficiency of nuclear factor of activated T cells 1 (NFAT1). NFAT1, encoded by NFATC2, mediates calcium-calcineurin signals that drive cell activation, proliferation, and survival. The patient is homozygous for a damaging germline NFATC2 variant (c.2023_2026delTACC; p.Tyr675Thrfs∗18) and presented with joint contractures, osteochondromas, and recurrent B-cell lymphoma. Absence of NFAT1 protein in chondrocytes caused enrichment in prosurvival and inflammatory genes. Systematic single-cell-omic analyses in PBMCs revealed an environment that promotes lymphomagenesis with accumulation of naïve B cells (enriched for oncogenic signatures MYC and JAK1), exhausted CD4+ T cells, impaired T follicular helper cells, and aberrant CD8+ T cells. This work highlights the pleiotropic role of human NFAT1, will empower the diagnosis of additional patients with NFAT1 deficiency, and further defines the detrimental effects associated with long-term use of calcineurin inhibitors.

Associations Between Maternal Stressful Life Events and Perceived Distress during Pregnancy and Child Mental Health at Age 4.

Accumulating evidence suggests that maternal exposure to objectively stressful events and subjective distress during pregnancy may have intergenerational impacts on children's mental health, yet evidence is limited. In a multisite longitudinal cohort (N = 454), we used multi-variable linear regression models to evaluate the predictive value of exposure to stressful events and perceived distress in pregnancy for children's internalizing problems, externalizing problems, and adaptive skills at age 4. We also explored two- and three-way interactions between stressful events, distress, and child sex. Both objective and subjective maternal stress independently predicted children's behavior, with more stressful events and higher distress predicting more internalizing and externalizing problems and worse adaptability; stress types did not significantly interact. There was some evidence that more stressful events predicted higher externalizing behaviors only for girls. Three-way interactions were not significant. The current findings highlight the importance of considering the type of stress measurement being used (e.g., counts of objective event exposure or subjective perceptions), suggest prenatal stress effects may be transdiagnostic, and meet calls for rigor and reproducibility by confirming these independent main effects in a relatively large group of families across multiple U.S. regions. Results point to adversity prevention having a two-generation impact and that pre- and postnatal family-focused intervention targets may help curb the rising rates of children's mental health problems.

Low-grade diffusely infiltrative tumour (LGDIT), SMARCB1-mutant: A clinical and histopathological distinct entity showing epigenetic similarity with ATRT-MYC.

Low-grade diffusely infiltrative tumour (LGDIT), SMARCB1-mutant, is a histopathological distinct low-grade lesion encountered in older children and young adults that shows epigenetic similarity with ATRT-MYC and has the potential for malignant progression.

Accuracy of central neuro-imaging review of DIPG compared with histopathology in the International DIPG Registry.

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) remains a clinico-radiologic diagnosis without routine tissue acquisition. Reliable imaging distinction between DIPG and other pontine tumors with potentially more favorable prognoses and treatment considerations is essential. METHODS: Cases submitted to the International DIPG registry (IDIPGR) with histopathologic and/or radiologic data were analyzed. Central imaging review was performed on diagnostic brain MRIs (if available) by two neuro-radiologists. Imaging features suggestive of alternative diagnoses included nonpontine origin, <50% pontine involvement, focally exophytic morphology, sharply defined margins, and/or marked diffusion restriction throughout. RESULTS: Among 286 patients with pathology from biopsy and/or autopsy, 23 (8%) had histologic diagnoses inconsistent with DIPG, most commonly nondiffuse low-grade gliomas and embryonal tumors. Among 569 patients with centrally-reviewed diagnostic MRIs, 40 (7%) were classified as non-DIPG, alternative diagnosis suspected. The combined analysis included 151 patients with both histopathology and centrally-reviewed MRI. Of 77 patients with imaging classified as characteristic of DIPG, 76 (99%) had histopathologic diagnoses consistent with DIPG (infiltrating grade II-IV gliomas). Of 57 patients classified as likely DIPG with some unusual imaging features, 55 (96%) had histopathologic diagnoses consistent with DIPG. Of 17 patients with imaging features suggestive of an alternative diagnosis, eight (47%) had histopathologic diagnoses inconsistent with DIPG (remaining patients were excluded due to nonpontine tumor origin). Association between central neuro-imaging review impression and histopathology was significant (p < 0.001), and central neuro-imaging impression was prognostic of overall survival. CONCLUSIONS: The accuracy and important role of central neuro-imaging review in confirming the diagnosis of DIPG is demonstrated.

Trametinib therapy for children with neurofibromatosis type 1 and life-threatening plexiform neurofibroma or treatment-refractory low-grade glioma.

PURPOSE: To describe a series of children with extensive PNF or treatment refractory PLGG treated on a compassionate basis with trametinib. METHODS: We report on six patients with NF-1 treated with trametinib on a compassionate basis at British Columbia Children's Hospital since 2017. Data were collected retrospectively from the patient record. RAPNO and volumetric criteria were used to evaluate the response of intracranial and extracranial lesions, respectively. RESULTS: Subjects were 21 months to 14 years old at the time of initiation of trametinib therapy and 3/6 subjects are male. Duration of therapy was 4-28 months at the time of this report. All patients had partial response or were stable on analysis. Two patients with life-threatening PNF had a partial radiographic response in tandem with significant clinical improvement and developmental catch up. One subject discontinued therapy after 6 months due to paronychia and inadequate response. The most common adverse effect (AE) was grade 1-2 paronychia or dermatitis in 5/6 patients. There were no grade 3 or 4 AEs. At the time of this report, five patients remain on therapy. CONCLUSION: Trametinib is an effective therapy for advanced PNF and refractory PLGG in patients with NF-1 and is well tolerated in children. Further data and clinical trials are required to assess tolerance, efficacy and durability of response, and length of treatment required in such patients.