Neurotrophic tyrosine receptor kinase(NTRK)gene variants have been reported in a variety of cancer types. The prevalence of NTRK gene variants is less than 1% in many types of solid cancer. The highest NTRK gene fusions frequencies were found in secretary breast carcinoma and infantile fibrosarcoma. There are several methods to detect NTRK gene variants, including RT-PCR, and comprehensive genome profiling. Two NTRK inhibitors, entrectinib and larotrectinib, are approved for NTRK gene fusion positive solid cancers in Japan. NTRK inhibitors provide a durable response, but duration of response may be limited by acquired resistance. A next-generation TRK inhibitors are expected to overcome acquired resistance.