Abstract: Objective To study the relationship of matrix metalloproteinase 7 （MMP7） expression to the infiltration and metastasis of malignant melanoma. Methods Various concentrations （10, 20, 30 μmol/L） of heparanase antisense oligodeoxynucleotide （ASODN） was used to transfect human malignant melanoma cell line A375. Then, the transfected cells were subcutaneously inoculated into the right back of nude mice. Six weeks after the inoculation, transplanted tumors were isolated from the mice, and the levels of MMP7 protein expression were assessed by SP immunohistochemistry. The expression rate of MMP7 was also examined by SP immunohistochemistry in A375 cells and in tissue samples from patients with malignant melanoma （n = 30）, junctional nevus （n = 30） and normal human controls （n = 15）. Results The expression rate of MMP-7 was 83.33% （25/30）, 6.67% （2/30） and 0 （0/15） respectively in malignant melanoma, junctional nevus and normal skin tissue samples; there was a significant difference in the positivity rate of MMP-7 between the malignant melanoma group and junctional nevus group （χ2 = 35.62, P = 0.000） as well as normal control group （χ2 = 28.12, P = 0.000）, but not between the junctional nevus group and normal control group （P > 0.05）. The expression of MMP-7 in transplanted tumor was decreased to a varying degreee by three levels of ASODN, and the inhibitory effects of 30 mol/L ASODN were the strongest （P < 0.05）. MMP-7 protein was also highly expressed in A375 cells. Conclusions The expression of MMP-7 in cutaneous malignant melanoma is higher than that in junctional nevus and normal skin tissue. Hpa-ASODN significantly inhibits the expression of MMP-7 in transplanted tumors in nude mice. MMP-7 is highly expressed in A375 cells.

Key words: melanoma, Cell line,tumor