High-grade glioma in infants and very young children: characteristics, treatment, and outcomes.

PURPOSE: High-grade gliomas in infants and very young children (less than 3 to 5 years old) pose significant challenges due to the limited scientific literature available and high risks associated with treatments. This study aims to investigate their characteristics, treatment, and outcomes. METHODS: A cohort study was conducted at Children's Cancer Hospital, Egypt. Cases included children aged < 5 years old with confirmed CNS high-grade glioma. Baseline clinical and radiological characteristics, besides potential prognostic factors were assessed. RESULTS: In total, 76 cases were identified, 7 of them were < 1 year old. Gross- or near-total resection (GTR/NTR) was achieved in 32.9% of all cases. Of the tested cases, H3K27M-alteration was present in 5 subjects only. The 3-year OS and EFS for all cases were 26.9% and 15.4%, respectively. Extent of resection was the most important prognostic factor, as those achieving GTR/NTR experienced more than double the survival compared to those who do not (p = 0.05). Age had a "bimodal" effect on EFS, with those aged 1 to 3 years old faring better than younger and older age groups. Subjects with midline tumors had worse survival compared to non-midline tumors (1-year EFS = 18.5% vs 35%, respectively, p = 0.02). CONCLUSION: This study in a large cohort of HGG in infants and very young children offers insights into the characteristics and treatment challenges. Extent of resection, age group, and tumor localization are important prognostic factors. Further research with larger sample size is warranted to refine treatment approaches and improve outcomes.

Hypofractionated Radiation Therapy For Diffuse Intrinsic Pontine Glioma: A Noninferiority Randomized Study Including 253 Children.

PURPOSE: Pediatric diffuse intrinsic pontine glioma is an orphen disease. This study aimed to confirm the noninferiority of hypofractionated (HF) radiation therapy. Identification of the prognostic factors that determine the overall survival (OS) and progression-free survival (PFS) was the secondary objective. METHODS AND MATERIALS: We randomized 253 patients into 3 arms of radiation therapy regimens: HF1, receiving 39 Gy in 13 fractions; HF2, receiving 45 Gy in 15 fractions; and conventional fractionation (CF), receiving 54 Gy in 30 fractions. The OS and PFS were calculated using Kaplan-Meier methods, and the noninferiority was estimated against the CF arm. RESULTS: The median OS for the HF1, HF2, and CF were 9.6, 8.2, and 8.7 months, respectively. The 1-, 1.5-, and 2-year OS were 34.6%, 17.9%, and 10.7% for HF1; 26.2%, 13.1%, and 4.8% for HF2; and 25.3%, 12.1%, and 8.4% for CF, respectively (P = .3). The hazard ratio was 0.776 and 1.124 for HF1 and HF2, respectively. Considering the noninferiority margin (Δ) of 15% and a power of 90%, the lower inferiority confidence interval for HF1 was -14.34% and for HF2 it was 11.37% (both below Δ), confirming its noninferiority at 18-months OS. Younger patients (2-5 years of age) had better median OS in the whole cohort (11.6 months), HF1 (13.5), and CF (12.1) but not HF2 (6.2) (P = .003). Furthermore, the OS rates at 1, 1.5, and 2 years for children 2 to 5 years of age in the HF2 arm were lower than those in the HF1 and CF arms. However, similar acute and late side effects were reported in the 3 arms. CONCLUSIONS: Two hypofractionated radiation therapy proved to be noninferior to conventional fractionation. Young age (2-5 years) is the only prognostic factor determining both OS and PFS. The young age superiority was lost with a higher hypofractionated radiation therapy dose, necessitating more caution in applying 45 Gy in 15 fractions in younger children (2-5 years of age).

Aggresomes predict poor outcomes and implicate proteostasis in the pathogenesis of pediatric choroid plexus tumors.

PURPOSE: Protein misfolding and aggregation result in proteotoxic stress and underlie the pathogenesis of many diseases. To overcome proteotoxicity, cells compartmentalize misfolded and aggregated proteins in different inclusion bodies. The aggresome is a paranuclear inclusion body that functions as a storage compartment for misfolded proteins. Choroid plexus tumors (CPTs) are rare neoplasms comprised of three pathological subgroups. The underlying mechanisms of their pathogenesis remain unclear. This study aims to elucidate the prognostic role and the biological effects of aggresomes in pediatric CPTs. METHODS: We examined the presence of aggresomes in 42 patient-derived tumor tissues by immunohistochemistry and we identified their impact on patients' outcomes. We then investigated the proteogenomics signature associated with aggresomes using whole-genome DNA methylation and proteomic analysis to define their role in the pathogenesis of pediatric CPTs. RESULTS: Aggresomes were detected in 64.2% of samples and were distributed among different pathological and molecular subgroups. The presence of aggresomes with different percentages was correlated with patients' outcomes. The ≥ 25% cutoff had the most significant impact on overall and event-free survival (p-value < 0.001) compared to the pathological and the molecular stratifications. CONCLUSIONS: These results support the role of aggresome as a novel prognostic molecular marker for pediatric CPTs that was comparable to the molecular classification in segregating samples into two distinct subgroups, and to the pathological stratification in the prediction of patients' outcomes. Moreover, the proteogenomic signature of CPTs displayed altered protein homeostasis, manifested by enrichment in processes related to protein quality control.

Histone H3K27M Mutation Overrides Histological Grading in Pediatric Gliomas.

Pediatric high-grade gliomas (HGG) are rare aggressive tumors that present a prognostic and therapeutic challenge. Diffuse midline glioma, H3K27M-mutant is a new entity introduced to HGG in the latest WHO classification. In this study we evaluated the presence of H3K27M mutation in 105 tumor samples histologically classified into low-grade gliomas (LGG) (n = 45), and HGG (n = 60). Samples were screened for the mutation in histone H3.3 and H3.1 variants to examine its prevalence, prognostic impact, and assess its potential clinical value in limited resource settings. H3K27M mutation was detected in 28 of 105 (26.7%) samples, and its distribution was significantly associated with midline locations (p-value < 0.0001) and HGG (p-value = 0.003). Overall and event- free survival (OS and EFS, respectively) of patients with mutant tumors did not differ significantly, neither according to histologic grade (OS p-value = 0.736, EFS p-value = 0.75) nor across anatomical sites (OS p-value = 0.068, EFS p-value = 0.153). Detection of H3K27M mutation in pediatric gliomas provides more precise risk stratification compared to traditional histopathological techniques. Hence, mutation detection should be pursued in all pediatric gliomas. Meanwhile, focusing on midline LGG can be an alternative in lower-middle-income countries to maximally optimize patients' treatment options.

Association of Aggresomes with Survival Outcomes in Pediatric Medulloblastoma.

Aggresomes are inclusion bodies for misfolded/aggregated proteins. Despite the role of misfolded/aggregated proteins in neurological disorders, their role in cancer pathogenesis is poorly defined. In the current study we aimed to investigate whether aggresomes-positivity could be used to improve the disease subclassification and prognosis prediction of pediatric medulloblastoma. Ninety three pediatric medulloblastoma tumor samples were retrospectively stratified into three molecular subgroups; WNT, SHH and non-WNT/non-SHH, using immunohistochemistry and Multiplex Ligation Probe Amplification. Formation of aggresomes were detected using immunohistochemistry. Overall survival (OS) and event-free survival (EFS) were determined according to risk stratification criteria. Multivariate Cox regression analyses were carried out to exclude confounders. Aggresomes formation was detected in 63.4% (n = 59/93) of samples. Aggresomes were non-randomly distributed among different molecular subgroups (P = 0.00002). Multivariate Cox model identified aggresomes' percentage at ≥20% to be significantly correlated with patient outcome in both OS (HR = 3.419; 95% CI, 1.30-8.93; P = 0.01) and EFS (HR = 3; 95% CI, 1.19-7.53; P = 0.02). The presence of aggresomes in ≥20% of the tumor identified poor responders in standard risk patients; OS (P = 0.02) and EFS (P = 0.06), and significantly correlated with poor outcome in non-WNT/non-SHH molecular subgroup; OS (P = 0.0002) and EFS (P = 0.0004).