ID #1160 Assessment of Circulating Notch3 Extracellular Domain in Pediatric Low-Grade Glioma Patients
Maxine Gonzalez-Vega, Sydney Roher, Christian Nieves-Rivera, Avery WrightAbstract
Background
Pediatric low-grade gliomas (LGGs) are the most common central nervous system tumors in children. While most cases harbor alterations within the mitogen-activated protein kinase (MAPK) signaling pathway, emerging evidence highlights the importance of non-BRAF genetic variants and their influence on tumor biology. Although LGGs are typically non-malignant, they often behave as chronic, lifelong diseases, requiring sustained monitoring and therapeutic management to preserve quality of life. Recent findings suggest an association between FGFR1 mutations and spontaneous hemorrhage in LGG patients, underscoring the need for deeper investigation into underlying mechanisms and potential early biomarkers of disease progression. The Notch signaling pathway, known for its critical role in maintaining neurovascular integrity and its involvement in glioma oncogenesis, represents one such area of interest. Notably, circulating levels of the Notch3 extracellular domain (N3ECD), implicated in vascular disorders such as CADASIL, may offer a promising yet underexplored biomarker for neurovascular compromise in this patient population.
Methods
Serum samples were obtained from nine pediatric patients diagnosed with pilocytic astrocytoma at the time of initial diagnosis or surgical resection. All participants were enrolled under the Pediatric Neuro-Oncology IRBapproved protocol, and biospecimens were obtained from our local biotrust, where they were stored at –140 °C. Circulating N3ECD levels were quantified following the protocol described by Primo et al. (2015) using an enzyme-linked immunosorbent assay (ELISA). Protein concentrations were determined by comparing sample optical densities against a standard curve ranging from 100 to 1.562 ng/mL. Samples were subsequently stratified according to tumor mutational status, specifically KIAA1549::BRAF fusions and FGFR1 point mutations.
Results
Circulating N3ECD was detectable in the serum of all nine pediatric low-grade glioma patients (mean age: 3,431 ± 2,065 days, males:33% and females:66%). Tumors harboring the KIAA1549::BRAF fusion exhibited significantly lower circulating N3ECD levels (49.02 ± 38.99 ng/mL; n = 4) compared with tumors containing FGFR1 mutations (125.5 ± 72.55 ng/mL; n = 5).
Conclusion
Differences between KIAA1549::BRAF fusion–positive and FGFR1-mutant low-grade gliomas suggest that mutation profile may influence Notch3 signaling. Serum N3ECD levels trended upward with age, indicating that its detection in this young population may reflect an underlying neurovascular abnormality. Prior studies linking FGFR mutations to increased risk of hemorrhage further support a role for vascular fragility in these tumors. Overall, these findings highlight variability in circulating N3ECD and suggest its potential as a minimally invasive biomarker, warranting validation in a larger cohort and in combination with additional Notch pathway markers such as Jagged-1.