Extracellular matrix metalloproteinase inducer: a novel poor prognostic marker for human seminomas

Objective Extracellular matrix metalloproteinase inducer (EMMPRIN) is a glycosylated member of the immunoglobulin superfamily whose function in human seminomas is unknown. We have recently determined that EMMPRIN possesses the ability to stimulate fibroblast and endothelial cell matrix metalloproteinase production, and that its expression was frequently up-regulated in several tumours of the urinary system. Thus, EMMPRIN expression might be associated with the progression of human seminomas. The aim of this study was to investigate whether the presence of EMMPRIN in seminoma tissues might help to predict the patients' prognosis. Methods Paraffin-embedded tissues from 65 patients with seminomas and 20 normal testes were processed for immunohistochemical staining using a mouse monoclonal antibody generated against human EMMPRIN, as primary antibody, and a biotinylated goat-anti-mouse IgG, as secondary antibody. In addition, the correlation of EMMPRIN expression with clinicopathologic characteristics and patients' prognosis was also analysed. Results EMMPRIN was detected in cancerous tissues of 53 patients with seminoma, but not normal testes. Thirty-five patients showed weakly to moderately positive and 18 patients intensely positive expression. Moreover, positive EMMPRIN staining correlated significantly with various clinicopathological factors (increased TNM stage and higher histological differentiation type) as well as decreased tumour-specific survival (log-rank, p=0.02). In particular, EMMPRIN expression was an independent prognosticator as shown by Cox regression analysis (p<0.001). Conclusion EMMPRIN expression in a primary tumour predicts an unfavourable prognosis in human seminoma, suggesting its crucial role in the progression of this tumour.