CLSTN1 and age-related macular degeneration: Our MRM results confirmed the up-regulation in AMD and ERM of proteins involved in neuronal cell adhesion (CSTN1, CDH2, SPON1), retinal cell-cell adhesion (XLRS1), and integrin-mediated cell adhesion (LGALS3BP), suggesting that these proteins are potential biomarkers to discriminate between DR and the other disease groups.