CD74 and lung cancer: The utility of targeting NTRK1 was first described by Vaishnavi et al. in lung cancer where the authors identified oncogenic fusions involving MPRIP-NTRK1 and CD74-NTRK1, leading to constitutive activation of the kinase domain of the NTRK1 expression product, TrkA.18 The relevance of this finding was demonstrated in 3 of 91 lung cancer patients with newly diagnosed NTRK1 fusions.