Immunohistochemical study on ADAM33 in sinonasal inverted papillomas and squamous cell carcinomas of the larynx.

INTRODUCTION ADAM33 protein is a member of the family of transmembrane glycoproteins composed of multidomains. Members of the ADAM family have different activities, such as proteolysis and adhesion, making them good candidates to mediate the extracellular matrix remodeling and changes in cellular adhesion that characterize certain pathologies and cancer development. MATERIAL AND METHODS The immunohistochemical method was used to examine the immunoexpression of ADAM33 in 39 formalin-fixed, paraffin-embedded tissue specimens of sinonasal inverted papillomas (IP), 44 laryngeal squamous cell carcinomas (GI grade = 11, GII grade = 33) and 14 disease-free tissue specimens as a control. RESULTS The immunoexpression of ADAM33 was localized in the epithelial cells, mesenchymal cells of the vessels and infrequently in the stromal cells. The majority of the ADAM33 was localized intracellularly, although membrane immunoexpression was also noted. All epithelial and vascular staining scores were found to be significantly increased in GI and GII grades of laryngeal cancer compared with controls (p < 0.001) and IP (p < 0.001). No statistically significant differences were found in immunoexpression of ADAM33 between GI and GII tumors. The immunoexpression of ADAM33 was significantly higher in IP patients than in controls (p < 0.02). CONCLUSIONS Our findings suggest that ADAM33 could potentially contribute to tumorigenesis of the laryngeal and sinonasal region.