NTRK1 and soft tissue sarcoma: Targeted therapy with a kinase inhibitor leads to a response in a majority of patients with NTRK1/2/3 gene fusion-positive cancers [12, 13, 18, 36] and because limited treatment options are available for the vast majority of soft tissue sarcomas detection of tumors harboring NTRK1-3 fusions results in a tremendous treatment benefit.