NTRK1 and glioblastoma: Multiple Receptor tyrosine Kinases, including EGFR and PDGFR, have been validated as therapeutic targets for GBM and BCBM, yet these RTK inhibitors have had limited success in the clinic.1,5,33–38 Additionally, increased IGF1R expression/activation is known to mediate resistance to RTK inhibitors, chemotherapy, and radiotherapy.