NTRK Fusion-positive Non-small-cell Lung Cancer: The Diagnosis and Targeted Therapy.

In cases of non-small-cell lung cancer (NSCLC), molecular-targeted therapy has shown remarkable improvements in the survival and safety compared with conventional chemotherapy. Recently, the tropomyosin receptor kinase (TRK) inhibitors entrectinib and larotrectinib were approved in the United States, Europe, and elsewhere for patients with a neurotrophic tropomyosin-related kinases (NTRK) gene fusion-positive solid tumors, including NSCLC. Furthermore, next-generation TRK inhibitors that are sensitive to certain secondary mutations mediating resistance to entrectinib or larotrectinib are also being tested in ongoing clinical trials. Although the prevalence of NTRK gene fusions among patients with NSCLC is only approximately 1%, the detection of NTRK gene fusions has become more important with the development of such TRK inhibitors. In the present review, we summarize the various diagnostic techniques for NTRK gene fusion and the effects of TRK inhibitors in NTRK fusion-positive NSCLC.