Among the cysteine proteases, the cathepsins are known to promote the metastasis of tumour cells by enhancing extracellular matrix degradation [33,34]; and EpCAM has been demonstrated to function as a membrane-bound protease inhibitor that can inhibit cathepsins either by binding to active site cleft of cathepsin via its TY domain; or serving as a “decoy” substrate whereby cathepsins can cleave the Arg80/Arg81 bond [35]. This evidence concerns the gene CTSS and neoplasm.