The reason for context-specific effects of individual cathepsins in tumors might well be the fact that these proteases play contrasting roles in carcinogenesis by acting as positive mediators of invasion (pro-tumor), as positive or negative regulators of proliferation (pro- or anti-tumor effect), and, in addition, may affect cell death (Goulet et al., 2004; Vasiljeva and Turk, 2008; Vasiljeva et al., 2008; Turk and Turk, 2009). Here, CTSS is linked to neoplasm.