More recently, we reported that Cathepsin L (CTSL) expression was significantly reduced in lung fibroblasts and tissues derived from SSc patients, in part due to constitutive suppression by the TGFβ/Smad pathway, and that the lack of availability of CTSL in the extracellular milieu prevented the release of the anti-fibrotic protein endostatin [14]. This evidence concerns the gene TGFB1 and systemic sclerosis.