Given the extremely low frequency of NTRK fusions among lung cancer patients on one hand and the significant clinical benefit of Trk inhibitor treatment in NTRK-fusion-positive patients on the other hand, it is extremely important to establish a diagnostic algorithm that is sensitive and specific, tissue-sparing, and cost- and time-efficient and that allows reliable testing in a routine environment. This evidence concerns the gene NTRK1 and lung carcinoma.