Here we report the identification of a secondary mutation in ALK, F1174L, as one cause of crizotinib resistance in a patient with an inflammatory myofibroblastic tumor (IMT) harboring a RANBP2-ALK translocation who progressed while on crizotinib therapy.     ///    "Furthermore, the F1174L mutation inhibits crizotinib-mediated downregulation of ALK signaling and blocks apoptosis in RANBP2-ALK Ba/F3 cells. "