Tachykinin receptor 3 distribution in human oral squamous cell carcinoma

Background: Tachykinin 3 (TAC3) and its preferred tachykinin receptor 3 (TACR3) that are prominently detected in the central nervous system, play significant roles in physiological development and specifically in the human reproductive system. The roles of TAC3/TACR3 in oral squamous cell carcinoma are unknown. Materials and Methods: We examined the expression pattern of TAC3/TACR3 in clinically-resected oral squamous cell carcinoma samples using immunohistochemistry and immunofluorescence analysis. Results: We found that even though the expression level of TACR3 was negative in the normal epithelium, it was highly elevated in tumor cells. A more intense signal was observed in the invasive front of tumor cells that had migrated into the mandible bone matrix. TAC3 was not detected in tumor cells, but was expressed in PGP-9.5-positive sensory nerves in the mandible. Conclusion: Our results suggest that peripheral sensory nerve-derived TAC3 may affect gingival oral squamous cell carcinoma cells through TACR3 in the bone matrix.