A total of 10 proinflammatory cytokines, including matrix metalloproteinase 9, serine protease E1, IL-6, hepatocyte growth factor, VEGFA, VEGFR2, platelet endothelial cell adhesion molecule 1, C-reactive protein, chemokine ligand 2, and platelet-derived growth factor-AA (PDGF-AA), are significantly upregulated in patients with nasolacrimal duct obstruction (nasoLDO) (30). Here, PECAM1 is linked to Nasolacrimal duct obstruction.