In both HCC PDX and orthotopic mouse models, ROS1 inhibitor treatment markedly suppressed RNase7-induced tumorigenesis and led to decreased plasma RNase7 level with tumor shrinkage in mice….RNase7 serves as a high-affinity ligand for ROS1, and plasma RNase7 has the potential to function as a biomarker to stratify HCC patients for anti-ROS1 treatment.