These neurotrophic factors bind to specific high-affinity receptors expressed on neuronal fibers, such as tropomyosin receptor kinase A (TrkA) for NGF and tropomyosin receptor kinase B (TrkB) for BDNF, subsequently promoting nerve sprouting, elongation, and providing chemotactic cues that guide tumor cell migration along neural pathways [16,39,51,52]. The gene discussed is NTRK2; the disease is neoplasm.