Furthermore myofibroblasts in PDR and proliferative vitreoretinopathy membranes express MCP-1 and stromal-cell-derived-factor- (SDF-) 1, and vascular endothelial cells in PDR membranes express MCP-1, SDF-1, and the chemokine receptor CXCR3. This evidence concerns the gene CCL2 and proliferative vitreoretinopathy.