The level of plasma PEDF increased as the stage of diabetic retinopathy advanced: 5.29±5.10 μg/ml in patients with NDR (n=20, 63.9±10.3 years); 5.07±4.37 μg/ml in patients with M-NPDR (n=37, 66.6±9.1 years); 6.61±6.20 μg/ml in patients with S-NPDR (n=98, 62.9±8.1 years); and 7.69±6.14 μg/ml in patients with PDR (n=88, 57.9±9.7 years) (Figure 1A). This evidence concerns the gene SERPINF1 and diabetic retinopathy.