Zinc-alpha-2-glycoprotein (AZGP1) (Sanchez et al. 1997), a 41 kDa protein secreted in many bodily fluids, is thought to stimulate lipolysis and be the cause of the excessive fat loss seen in cancer cachexia (Russell et al. 2004). AZGP1 is able to bind prolactin-inducible protein (PIP) (Myal et al. 1991), another secreted protein overexpressed in certain breast cancers (Hassan et al. 2008, Debily et al. 2009).