mRNA expression of brain-derived neurotrophic factor (BDNF) and NTRK2, protein synthesis of NTRK2 in head and neck squamous cell carcinoma (HNSCC) ( A , B ): In situ hybridization of antisense ( A ) and sense ( B ) riboprobe for BDNF (blue) in larynx SCC, cell nuclei counterstained in nuclear fast red. The antisense probe shows intensive purple—blue reactive areas, while the tissue reacted with the sense probe is slightly purple—blue stained. ( C ): In situ hybridization of antisense BDNF riboprobe and ( D ): immunohistochemistry of TrkB (brown) in tumor cell nests of oral SCC. A and B and C and D are sequential sections. ( E ): PCR detection of BDNF (519 base pairs, bps), NTRK2 (full protein coding area, 2528 bps) normalized to loading control ACTB (534 bps, not shown, normalized values represented as column bars) gene expression in cDNA samples of control UPPP normal mucosa, immunohistochemically (IHC) TrkB-positive and TrkB-negative HNSCC. BDNF is expressed in both normal and malignant tissue, NTRK2 is not present in normal mucosa, but if positive TrkB IHC staining was detected, the NTRK2 gene expression was also confirmed by PCR, while TrkB-negative IHC was also negative in RT-PCR. ( A – D ) images were taken by the TissueFaxs system, bars: 200 µm: ( A , B ); 100 µm: ( C , D ). Bands densitometry was done using Azurespot 14.2.
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