NTRK1 and cancer: The resulting activated downstream signaling is believed to be a strong driver for these cancers, indicated by impressive response rates seen in NTRK gene fusion-positive cancer patients after treatment with selective TRK inhibitors, such as larotrectinib (71% response rate, with a median duration of response 35 months) and entrectinib (57% response rate with a median duration of response of 10 months) [16,17].