TGFB1 and systemic sclerosis: Investigation of the role of TGF-β signaling in the induction of a fibrotic phenotype in SSc fibroblasts using small molecule inhibitors, antibodies, siRNA directed against the TGF-β receptors or SMADs as well as knockout mouse models has indicated the involvement and dysregulation of both canonical [36–38] and non-canonical [39–41] pathways.