CBL mutations in pediatric solid and CNS tumors are a marker of receptor tyrosine kinase activation and a potential therapeutic target

Mutations in CBL, an E3 ubiquitin ligase that negatively regulates receptor tyrosine kinases (RTKs) and potentiates intracellular signaling, have been extensively characterized in hematological malignancies. However, the impacts are unknown in other cancer types. We have identified established and novel aberrations in CBL in molecularly diverse pediatric CNS and solid tumors. Additionally, we present novel CBL splice mutations, including in the germline of a high-grade glioma patient, and alternative CBL splicing without corresponding genomic alterations. Functionally, we demonstrate that CBL exon 8/9{Delta}, typically associated with acute myeloid leukemia, is RTK activating in neuroblastoma and that novel CBL variants, CBL E366_E373del and CBL C384G, can cooperate with overexpression of EGFR to transform Ba/F3 cells. Collectively, these data represent a novel form of RTK activation in pediatric patients with solid and CNS tumors who might benefit from RTK-targeted therapies. Statement of significanceMolecularly targeted therapies improve childhood cancer outcomes. Therapies targeting genes called receptor tyrosine kinases are particularly effective. We have identified new genetic alterations that may be a marker for receptor tyrosine kinase activation and drug sensitivity, enabling more patients to benefit from targeted treatments.