NTRK1 and gastrointestinal stromal tumor: The activity of lenvatinib, another broad spectrum TKI targeting KIT, RET, PDGFRA, VEGFR 1–3 and FGFR 1–4 receptor tyrosine kinases, in still under evaluation in a multicenter, placebo-controlled, double-blinded phase II study of imatinib and sunitinib-refractory GIST patients (LENVAGIST) [66].