Immunohistochemical Expression of MMP-2 and MMP-9 Metalloproteinases in Melanocytic Nevi and Malignant Melanomas

Shin, Bong Seok; Park, Man Kyu; Choi, Kyu Chul; Chung, Byoung Soo

Abstract

BACKGROUND
One of the most important steps in neoplastic progression is represented by invasion of surrounding normal tissues by neoplastic cells. Enzymes such as the metalloproteinases(MMPs) are thought to be involved in the process of destruction of basement membranes and stromal invasion by tumor cells. OBJECTIVE: We investigated the expression patterns of MMP-2 and MMP-9 in acquired and congenital melanocytic nevi, and malignant melanoma by immunohistochemical technique. METHOD: Formalin-fixed and paraffin-embedded tissues from 4 junctional nevi, 4 compound nevi, 5 intradermal nevi, 6 congenital melanocytic nevi, and 6 malignant melanomas were immunolabelled with monoclonal antibodies directed against MMP-2 and MMP-9. RESULT: The benign melanocytic nevi showed negative or low expression for MMP-2 and MMP-9 with the exception of positive staining in involuting neuroid intradermal nevus, and the expression of MMP-9 was detected in 3 cases of congenital melanocytic nevi. The malignant melanoma exhibited high expression of MMP-2 with variable intensity of reactivity in different areas of the tumors and MMP-9 was found to be focally expressed by the tumor cells in intraepidermal and dermoepidermal junction. These findings suggest that the expression of MMP-2 and MMP-9 may be related to tumorigenesis of melanocytic tumors and MMP-9 may be involved in the early stage of tumor progression.