Cathepsins and components of the plasminogen activator and inhibitor system have been demonstrated in various malignant tissues, e.g., breast cancer [28-30], lung cancer [31,32], head and neck cancer [33], ovarian cancer [34], gastric cancer [35-38] or CRC [39-45] and might therefore be useful as a diagnostic tool. Here, CTSS is linked to colorectal carcinoma.