In this context, many pediatric gliomas are characterized by hotspot driver mutations (H3.1/H3.3_K27M, H3.3_G34R/V, BRAF_V600E, IDH1_R132H)6 or by single fusion events (ETV6:NTRK3, KIAA1549:BRAF).7,8 This makes them perfect candidates for the use of ctDNA to monitor treatment response enabling early detection of tumor progression over the course of the disease. Here, NTRK3 is linked to central nervous system cancer.