NTRK1 and head and neck squamous cell carcinoma: In contrast to NTRK1, which was broadly distributed (Figure 1D,E), about the half of the HNSCC cases did not synthesize p75NTR in their epithelial cancer cell nests (an example is visible in Figure 3A), whereas it was detected in stroma, or at the border of the cancer cell nests (Figure 3A,C).