Abstract: Objectives To investigate HPV infection and its correlation with the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibito r of metalloproteinase-1 (TIMP-1) in vulvar squamous cell carcinoma (VSCC).Methods HPV6/11 and 16/18 DNA were detected using in situ hybridization in 26 cases of VSCC, 21 cases of vulvar intraepithelial neoplasia (VIN) and 10 specimens of normal skin.The expression of MMP-9 and TIMP-1 was measured by immunohistochemical method in these three groups.Results The infection rates of HPV6/11 and 16/18 in VSCC and VIN were 69.23% (18/26) and 38.46% (10/26), 42.86% (9/21) and 28.57% (6/21) respectively, and no HPV6/11 or 16/18 DNA was discovered in normal skin epidermis.The expression rates of MMP-9 and TIMP-1 in VSCC, VIN and normal skin epidermis were 92.31%(24/26) and 76.92% (20/26), 90.45% (19/21) and 80.95% (17/21), and 80.00% (8/10) and 50.00% (5/10) respectively.MMP-9 expression in HPV positive lesions was higher than that in HPV negative lesions, but no significant difference of TIMP-1 expression was observed in HPV positive and negative lesions.Conclusions HPV infection may play a role in the development of VSCC.The higher expression of MMP-9 comparing with that of TIMP-1 may be an early marker of tumor progression in VSCC, and HPV infection may facilitate the invas ion and metastasis of VSCC.

Key words: Carcinoma,squamous cell, Papillomavirus,human, Gelatinase B, Tissue-inhibitor of metalloproteinase-1