Nicotinic Acetylcholine Receptors in Head and Neck Cancer and Their Correlation to Tumor Site and Progression.

BACKGROUND: Nicotine contributes to tumorigenesis through stimulation of nicotinic acetylcholine receptors (nAChRs) in head and neck squamous cell carcinoma (SCC). Although many factors have been found to be involved in the pathogenesis of head and neck cancer, the effect of nAChRs is still unclear. The study provides information on different subtypes in SCC and normal mucosa (NM) and their clinicopathological correlation to tumor progression.

METHODS: SCC (n = 34) of oropharynx, hypopharynx, larynx and corresponding NM (n = 38) were analyzed by quantitative real-time polymerase chain reaction, immunoblotting and immunohistochemistry and correlated to tumor grading and Union for International Cancer Control (UICC) stage.

RESULTS: nAChR subtypes α1, α3, α5 and α7 were found in NM and SCC of the upper aerodigestive tract with high rates of α1 and α5 in SCC. An overexpression of α1 was found in laryngeal and hypopharyngeal SCC, while α3 and α7 subunits were downregulated. The expression of α1 and α5 subunits increased with tumor progression.

CONCLUSION: The nAChR subunit pattern shows a difference between NM and SCC and changes in the process of tumor progression. Therefore, it is conceivable that it contributes to tumorigenesis. The findings provide a basis for further studies in prognostic assessment and identifying carcinogenic changes from NM to SCC.