Established SSc biomarkers include collagen I (Col I) and α-smooth muscle actin (α-SMA) for fibrotic progression, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) for inflammatory activity, platelet endothelial cell adhesion molecule-1 (CD31) for vascular integrity, and anti-centromere antibody (ACA) for systemic autoimmunity [20,21,22,23]. Here, PECAM1 is linked to systemic sclerosis.