ALK and glioma: We find that infant gliomas comprise three main subgroups: (1) hemispheric receptor tyrosine kinase (RTK)-driven tumors, including ALK, ROS1, NTRK, and MET fusions, which are enriched for HGG and have an intermediate clinical outcome, (2) hemispheric RAS/MAPK-driven tumors, which show excellent long-term survival with minimal clinical intervention post-surgery, and (3) midline RAS/MAPK-driven tumors, which are enriched for LGG with BRAF alterations and have a relatively poor outcome even after conventional chemotherapeutic approaches.