To investigate the expression of methyltransferase-like 3 (METTL3) in cerebrospinal fluids (CSF) and its correlation with the prognosis of children with medulloblastoma (MB).

Cerebrospinal fluids were collected from MB children. METTL3 protein levels were quantified using the Enzyme-Linked ImmunoSorbent Assay (ELISA) and its correlations with clinicopathological features were analyzed. The prognostic significance was evaluated via the Kaplan-Meier survival curve and Cox proportional hazards regression. Bioinformatics analysis was conducted to assess the association of METTL3 with chemotherapeutic drug sensitivities and functional enrichment of METTL3 in brain tumors.

Ki-67 index was the only clinicopathological factor significantly correlated with CSF METTL3 levels (P<0.05). METTL3 high expression group showed superior progression-free survival (PFS) (HR=0.376, 95% CI:0.133-1.064, P<0.05). Cox analysis identified METTL3 expression as an independent prognostic factor for PFS (P<0.05). Significant negative correlations between METTL3 expression and 50% inhibitory concentrations (IC₅₀) of methotrexate/vinblastine/etoposide (P<0.001). Gene enrichment revealed METTL3′s involvement in neural development and Notch signaling pathways.

METTL3 might serve as a prognostic biomarker for MB pediatric patients. Further validation with expanded cohorts and mechanistic studies (in vivo/in vitro) is warranted.