NTRK2 and head and neck squamous cell carcinoma: Both the role of the BDNF/TrkB axis in chemotherapy resistance and lymphovascular metastasis of HNSCC [13,16,22] and a potential of oncogenic gene fusion of neurotrophin receptors [23] warrant investigation into the rationale for BDNF/NTRK2-targeted therapy in the treatment of HNSCC.