Expression of matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitor of MMP (TIMP)-1 in conjunctival melanomas and clinical implications.

PURPOSE

To investigate the expression of matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 in conjunctival melanomas and their correlations with clinicopathologic parameters and prognosis.

METHODS

Fourteen conjunctival melanoma tissue samples and nine conjunctival nevus tissue samples were stained immunohistochemically for MMP-2, MMP-9, and TIMP-1. Association of MMP-2, MMP-9, and TIMP-1 expression in melanoma tissues with clinical progression in terms of metastasis, recurrence, mitotic index, thickness, base diameter, and invasion depth was analyzed.

RESULTS

In the melanoma group, 78.6% of samples showed a positive reaction for MMP-2, 85.7% for MMP-9, and 100% for TIMP-1. In the nevus group, 11.1% showed a positive reaction for MMP-2, 66.7% for MMP-9, and 100% for TIMP-1. MMP-2 expression was significantly more induced in conjunctival melanoma than in benign nevi (P = 0.002). In conjunctival melanoma, MMP-9 expression was higher in tumors >1.5 mm thick (P = 0.026) and TIMP-1 expression was higher in recurrent cases (P = 0.03). There was no significant correlation between the expression and metastasis during the follow-up period (mean, 5 years).

CONCLUSION

MMP-2, MMP-9, and TIMP-1 were expressed in the majority of conjunctival melanomas, and MMP-2 might play a role in the development and clinical behavior of conjunctival melanoma.