Multi-cohort study of primary mismatch repair deficient gliomas in children, adolescents, and young adults

Gliomas are a major cause of cancer-related death among children, adolescents, and young adults (age 0-40 years). Primary mismatch repair deficiency (MMRD) is a pan-cancer mechanism with unique biology and therapeutic opportunities. A multi-cohort study in Toronto with validation in cohorts from St Jude Children’s Research Hospital and the Children’s Brain Tumor Network found that the prevalence of primary MMRD ranged between 3.7% and 12.4% in high-grade gliomas and was less than 1% in low-grade gliomas. MMRD was enriched in specific molecular subgroups and was associated with poor outcomes.