MMP9 and neoplasm: To further investigate the functional role of MMP2/9 in the immune response, we performed an in vitro T cell cytotoxicity-mediated tumor killing assay based on SK-MEL-28 melanoma cells in the presence of increasing concentrations of SB-3CT, which is known to inhibit gelatinases (MMP-2 and MMP-9) with high selectivity [36, 37].