Background and aims: Papilloma is frequently developed benign tumor of head and neck area but its potential for malignant transformation is still to be studied. The purpose of this study is to provide basic information for papillomas using immunohistochemical staining of MMP-2 and HPV 16/18.

Patients and methods: Selected papillomas were serially diagnosed with pre-cancerous papilloma (with epithelial dysplasia, pseudo-epitheliomatous hyperplasia) or malignant lesion (SCC) after first diagnosis (squamous papilloma, inverted papilloma). The selected tissues were stained with antibody to MMP-2 and HPV 16-E7, HPV 18-L1. Statistical analysis performed according to each transformation step, cancer stage and HPV 16/18 infection.

Results: Epithelial layer of papilloma and pre-cancerous papilloma lesions had similar MMP-2 expression but that of malignant lesion had significantly increased MMP-2 expression. There was no significant difference in MMP-2 expression of malignant lesions according to cancer stage classification. HPV 16 and 18 infection rates were 28.6%, 33.3% and 63.6% in papillomas, pre-cancerous papilloma lesions and SCC, respectively.

Conclusion: Relatively high MMP-2 expression and HPV 16 or 18 infection of papillomas may be associated with early events in multistep processes of malignant transformation of papillomas.

Conflict of interest: None declared.