The study also suggests that, instead of targeting cathepsins, mitigating tissue fibrosis by targeting TGF-β or its receptors may prove safer (Hill et al., 2001, Moon et al., 2006, Petersen et al., 2008, Russo et al., 2007), such as anti-TGF-β neutralizing antibody, endoglin (a TGF-β binding protein) antibody, soluble TGF-β type-II receptor, TGF-β antisense oligonucleotide, specific inhibitors of TGF-β receptor kinases (GW788388 and IN-1130), and pirfenidone (a small molecule TGF-β inhibitor), which recently received approval for the treatment of IPF (Carter, 2011). Here, CTSS is linked to idiopathic pulmonary fibrosis.