PATH-49. Clinical-demographic features and molecular classification of pediatric Medulloblastomas in a cohort from Western Mexico

Abstract INTRODUCTION Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in children. Its molecular classification (WNT, SHH, and non-WNT/non-SHH [NWS]) allows identification of subgroups with distinct clinical behavior. In Mexico and Latin America, the molecular characterization of MB remains limited. OBJECTIVE To describe the clinical and demographic characteristics of the pediatric MB population from Western Mexico and its molecular classification based on gene expression analysis. Methodology A total of 62 pediatric MB cases diagnosed between 2014 and 2024 were included. Clinical data (age, sex, symptoms, tumor location), histological subtype, and survival outcomes were collected. Molecular classification into WNT, SHH, and NWS groups was performed by RT-qPCR based on gene expression profiles. Overall survival was analyzed using Kaplan-Meier curves and the log-rank test. RESULTS The mean age in our cohort was 7.27 years (SD = 4.40); 69.4% were male. The most frequent age group was 3–9 years (40.3%). Histologically, the classic subtype predominated (62.9%). Molecular subgroup distribution was: WNT 11.3%, SHH 48.4%, and NWS 40.3%. Survival time ranged from 0 to 86 months; 60% of patients were alive at the time of analysis. Survival analysis showed no statistically significant differences according to age group, tumor location, or molecular subgroup. However, a significant difference was observed among histological subtypes, with the desmoplastic/nodular (D/N) variant associated with a better prognosis (p < 0.005). CONCLUSIONS The integration of clinical and molecular data enabled the identification of prognostically relevant patterns. Molecular classification by RT-qPCR is an accessible and valuable tool for risk stratification in developing countries.