NTRK1 and head and neck squamous cell carcinoma: The anti-TrkB rabbit monoclonal antibody (clone 80G2) from Cell Signaling Technologies revealed positive reaction in 42.74% of HNSCC tissue, the so-called pan-Trk antibody (EPR17341 by Abcam) suggested by Rudzinsky et al. for IHC of the protein products of NTRK rearrangements did not detect any positive reaction in any HNSCC tissue.