Increased expression of fascin associated with malignant transformation of sinonasal inverted papilloma

Background Fascin, an actin binding protein, usually expressed at a low level in normal epithelium, but is significantly increased in transformed epithelial cells and several common carcinomas. In this study, we examined the expression of fascin by immunohistochemistry in sinonasal epithelium with chronic inflammation (control group), exophytic papilloma (EP), inverted papilloma (IP) with dysplasia and cancerated IP (including carcinoma in situ and invasive squamous cell carcinoma, SCC), and furthermore investigated the relationship between fascin expression and formation of malignant IP.Methods Fascin expression was immunohistochemically detected using monoclonal antibody against fascin in 86 paraffin embedded tissues, including 10 cases of sinonasal mucosa with chronic inflammation, 10 of EP, 45 of IP with dysplasia (45 cases were divided into three groups: IP with mild dysplasia, IP with moderate dysplasia, and IP with severe dysplasia, 15 cases each), and 21 of cancerated IP.Results The level of fascin expression was significantly higher in the neoplastic tissue than that in control group. Fascin expression increased gradually with the progression from sinonasal epithelium with chronic inflammation, IP with mild dysplasia, IP with moderate dysplasia, IP with severe dysplasia, to cancerated IP, and significant difference of fascin expression was observed between any two groups of the five.Conclusion Precancerous lesions of IP exhibit elevated levels of fascin that may be associated with carcinogenesis of IP. Fascin may play a role in the formation of IP and EP.