Expression of matrix metalloproteinase-2 in renal cell carcinoma.

Background: Renal cell carcinoma (RCC) is a family of carcinomas arising from the renal tubular epithelium through different genetic lesions. The most common characterstics of RCC are hypervascularity, tendency to metastasize widely before giving rise to any symptoms or signs, and poor prognosis. It has been reported that matrix metallopropteinases (MMPs) are a family of endopeptidases implicated in tissue remodeling and cancer invasion. Therefore, the aim of the present study was to investigate the expression of MMP-2 in RCC and correlate its expression with the clinicopathologic prognostic parameters.

Material And Methods: Fifty cases of primary RCC comprised the material of this study. Formalin-fixed paraffin-embedded tissues were stained with MMP-2 immunostaining, using improved streptavidin-biotin amplified system. The intensity of staining and percentage of positive cells were assessed.

Results: MMP-2 was expressed as diffuse brown cytoplasmic staining in positive cells. The non-tumorous renal tissue showed negative staining whereas the tumor cells, fibroblasts and vascular endothelial cells showed immunoreactivity in positive cases. 43/50 RCC cases studied were positive for MMP-2. A positive correlation was observed between MMP-2 expression and tumor size, histologic type, capsular & vascular invasion and high levels of cellular proliferation.

Conclusion: It seems that MMP-2 is involved in tumor expansion phenomena associated with tumor progression, invasion of the microvasculature and distant metastasis of RCC.