NTRK1 and dendritic cell sarcoma: They identified a TFG–NTRK1 fusion in a 2-month-old patient with ECD, a TPR–NTRK1 fusion in a 20-year-old patient with interdigitating dendritic cell sarcoma, and UBE2R2–NTRK3 and HNRNPA2B1–NTRK3 fusions in 53- and 76-year-old patients with multiple myeloma.