NTRK1 and gastrointestinal stromal tumor: Imatinib mesylate (IM) (Gleevec), the non-selective receptor tyrosine kinase inhibitor (RTKi), is currently accepted as the first-line therapy for GIST patients with a reported response rate (RR) of ~50–70% and progression-free survival (PFS) of ~20 months [4,5,6].