Markers of malignant transformation of sinonasal inverted papilloma.

AIM: To measure HPV status, epidermal growth factor receptor (EGFR) and transforming growth factor-alpha (TGF-alpha) expression and Ki-67 index in exophytic papilloma (EP), inverted papilloma (IP) with dysplasia, IP with carcinoma and invasive squamous cell carcinoma (SCC).

METHODS: Forty-four patients with sinonasal papilloma and invasive SCC were selected. The nasal tissues were stained with monoclonal antibodies to EGFR, TGF-alpha and Ki-67. The results were analysed using quantitative immunohistochemical analysis. In situ hybridization studies for HPV DNA for 6/11, 16/18 and 31/33 were also performed on the tissue.

RESULTS: Significant increase of EGFR and TGF-alpha was observed in IP with severe dysplasia, IP with carcinoma and invasive SCC compared to IP with mild dysplasia and control nasal mucosa. And a serial upreguration in terms of Ki-67 index in IP with dysplasia was observed. Among IP, HPV 6/11-positive was present in 42% tumour and HPV 16/18-positive was present in 31% of tumours. Among HPV 6/11 and 16/18-positive IP, significant increase of EGFR and Ki-67 index were observed.

CONCLUSION: Pre-cancerous lesions of IP exhibited elevated levels of EGFR and TGF-alpha and these expression may be associated with early events in IP carcinogenesis. HPV infection may be an early event in a multistep process of malignant formation of IP.