PROS1 and cancer: In addition to direct loss of contractile protein, several of the molecules that signal elevated proteolysis in cancer cachexia, such as TNF-α (Llovera et al. 1998a) and NF-κB (Cai et al. 2004), have been shown to have depressive effects on muscle contractility (Wilcox et al. 1994; Reid et al. 2002; Cai et al. 2004; Hardin et al. 2008).