NTRK1 and sarcoma: However, the overall benefit of molecular testing in the diagnosis and clinical management of patients with sarcoma has been demonstrated in large multicenter studies, similar to what has been shown for lung cancer.57,58 While sequence-based testing methods (RNA MPS or RT-PCR) are recommended for the detection of productive NTRK gene rearrangements, IHC with a validated antibody against TRK proteins (most easily with a pan-TRK antibody) may be used as a fast and less expensive pre-screening tool.