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. The gene discussed is ETV6; the disease is central nervous system cancer.