Abstract: Objective To investigate the expression of osteopontin and matrix metalloproteinase-9 (MMP9),and the relationship of osteopontin and MMP9 in malignant melanoma.Methods Expression of osteopontin and MMP9 was measured by immunohistochemical SP method in 23 patients with primary cutaneous malignant melanoma,17 patients with metastatic melanoma and 20 patients with pigmented nevus.Results Osteopontin and MMP9 were expressed respectively in 87.5% and 75.0% of 40 malignant melanoma specimens,15.0% and 10.0% of 20 pigmented nevus specimens.The expression of both osteopontin and MMP9 was significantly higher (both P<0.05) in malignant melanoma than in pigmented nevus.There was no correlation between the expression of osteopontin and MMP9,with age,sex,lymph node metastasis or location of lesions (P>0.05).Twenty-nine cases were positive for both osteopontin and MMP9,4 negative for either osteopontin or MMP9.Conclusion Both osteopontin and MMP9 were overexpressed in malignant melanoma,but neither was related to lymph node metastasis.

Key words: Melanoma, Gelatinase B, Osteopontin