Immunohistochemical expression of matrix metalloproteinase-2 and -9 in melanocytic nevi is altered by ultraviolet B

Abstract

Background: Ultraviolet B (UVB) radiation can cause morphological and biological alterations similar to those of melanoma in situ in irradiated melanocytic nevi. matrix metalloproteinase (MMP-2) and -9 appear to be involved with tumour invasion, the formation of metastases and neoangiogenesis in melanomas. The effects of UVB on the immunohistochemical expression of gelatinases in different cell types in melanocytic nevi have not been completely studied. Purpose: Evaluate the effects of UVB on the immunohistochemical expression of MMP-2 and -9 in different cell types in melanocytic nevi. Methods: Forty-two melanocytic nevi had one half irradiated with 2 MEDsof UVB and were excised 1 week later. Three different observers compared the intensity of the immunohistochemical expression of gelatinases in keratinocytes, melanocytes, endothelial cells and fibroblasts on the irradiated (IS) and non-irradiated sides (NIS). Results: All the cell types showed an increase in the expression of MMP-2 on the IS, especially the epidermal melanocytes. No significant increase in the expression of MMP-9 in keratinocytes was detected on the IS; significant increase was observed in all the remaining cells. Conclusions: One single irradiation of UVB increases the immunohistochemical expression of gelatinases in almost all evaluated cell lines, with the exception of MMP-9 in keratinocytes. © 2007 Blackwell Munksgaard.