BDNF and neoplasm: In oral squamous cell carcinoma (OSCC), Trk receptors have been confirmed to be overexpressed: Tropomyosin receptor kinase A (NGF), TrkB (BDNF, NT-4/5), and TrkC (neurotrophins 3, NT3) receptors, TrkC and its ligand NTF3 can promote the proliferation of SCs by inhibiting the formation of myeloid cells in the peripheral nervous system, and TrkC may also participate in PNI by regulating the interaction between SCs and tumor cells [68].