Across 327 samples from multiple cancer types, Koopman and colleagues reported 84% specificity and 77% sensitivity for pan-Trk IHC compared to RNA- and DNA-based NGS [30]; with regard to false-negative cases, 6 out of 29 NTRK-rearranged tumors showed a negative pan-Trk stain (20.7%). Here, NTRK1 is linked to cancer.