Identification of a novel KLC1–ROS1 fusion in a case of pediatric low-grade localized glioma

The proto-oncogene tyrosine-protein kinase ROS1 (ROS1) is a tyrosine kinase that is closely related to anaplastic lymphoma kinase receptor (ALK). We describe a novel KLC1–ROS1 fusion identified in a case of pediatric low-grade glioma. This was detected by RNA sequencing and confirmed by reverse-transcription PCR and fluorescent in situ hybridization. Immunohistochemical staining for ROS1 was positive in the tumor cytoplasm. In vitro analysis demonstrated the oncogenic activity of this fusion, which was suppressed by the ALK/ROS1 inhibitor, crizotinib. Our case and others suggest that various ROS1 fusions might be present in a subset of pediatric gliomas, which could be targeted for therapy.