Milia-Argeiti E, Huet E, Labropoulou VT, et al. - Since there is a requirement to determine new prognostic biomarkers for testicular germ cell tumours, researchers examined matrix metalloproteinases MMP-2 and MMP-9 expression in testicular tumour tissues as well as cell lines of both seminoma and non-seminoma origin. Considerably more expression of MMP-2 and MMP-9 was detected in more invasive non-seminomatous teratocarcinoma and embryonal cells vs seminoma cells showing lower invasiveness. They also identified an inverse link between invasiveness and the expression of endogenous inhibitors TIMP (tissue inhibitor of metalloproteinases)-1 and TIMP-2. In all cell lines, Marimastat (MMP inhibitor)-induced inhibition of invasion was evident, the highest inhibition was seen in the more invasive NTERA2/D1 and NCCIT cells, which showed the highest ratio of MMP-2 and MMP-9 vs TIMP-1 and TIMP-2. Overall, the significance of MMP-2 and MMP-9 in the invasiveness of testicular tumours was shown, and the possible utility of their levels vs those of TIMP-1 and TIMP-2 to serve as potential biomarkers for testicular malignancy was also suggested.