EDN1 and systemic sclerosis: Various profibrotic growth factors and cytokines, such as endothelin‐1(ET‐1), platelet‐derived growth factor (PDGF), and interleukin‐6 (IL‐6), have been reported in the serum and skin of SSc patients that recruit the Ras signaling pathway, resulting in fibroblast proliferation and survival, increased collagen type I/III and ECM synthesis, and decreased expression of MMP‐1 [8, 9, 10].