NTRK1 and cancer: The family of Eph receptor tyrosine kinases and their ephrin ligands have important functions in axonal guidance, bone remodeling, immune system and cancer(Shiuan and Chen 2016), because of their binding relationship for either the glycosylphosphatidylinositol-linked ephrin-A ligands or the transmembrane-bound ephrin-B ligands, Ephs can be divided into two subclasses, EphAs and EphBs (Eph Nomenclature Committee 1997).