EDN1 and systemic sclerosis: Increased serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1) have been described in patients with SSc, and have been variably correlated with internal organ involvement, including pulmonary fibrosis [105–107].