NTRK2 and head and neck squamous cell carcinoma: Interestingly, the specific high affinity BDNF receptor, TrkB, was limitedly available, only in 40% of HNSCC, 1 of 12 normal mucosa samples, in Detroit 562 HNSCC cell line without any sign of positive reaction, in SCC-25 oral SCC cells in extremely rare positive cells, but in UPCI-SCC090 HPV+ oropharynx SCC cells in all cells.