CTSD and melanoma: Thus, on the bases of statistical analyses of the data obtained in four different primary (PM1-PM4) and metastatic (MM1-MM4) melanoma cell lines, we can conclude that: i) inhibitors of cathepsin D and L, as well as specific antibodies against both these proteases, were ineffective in reducing invasion capability of both primary and metastatic melanoma cell lines and that ii) either the chemical inhibitor of cathepsin B, CA-074, or specific anti-cathepsin B antibodies were able to significantly prevent the in vitro invasiveness of metastatic melanoma cell lines (Figure 3D).