As tumor-agnostic approval results in higher testing volumes, it has led to increased interest in optimizing testing regimes for NTRK-fusion. Fluorescence in situ hybridization (FISH) has been regarded as the gold standard in fusion detection, but in the case of NTRK-fusions, a FISH-analysis will require three different probes (NTRK1-3). This evidence concerns the gene NTRK1 and neoplasm.