['Increased serum concentrations of pigment epithelium-derived factor (PEDF) have been linked to the metabolic syndrome in the general population. However, the relationship between serum PEDF and nonalcoholic fatty liver disease (NAFLD), a hepatic manifestation of the metabolic syndrome, remains unknown.', 'We assayed serum PEDF levels in 156 patients with biopsy-proven NAFLD and 103 nonsteatotic control subjects who were matched for age and sex. The association between levels of PEDF and clinical, biochemical, and histological phenotypes was examined.', "NAFLD patients had significantly higher serum PEDF levels (1.97±0.50 μg/mL) than control subjects (1.51±0.49 μg/mL, Student's t test, P<0.001). Multivariable-adjusted stepwise regression analysis showed that PEDF ([beta]=0.32, t=3.13, P=0.002) and triglycerides ([beta]=0.22, t=2.23, P=0.02) were, in the order they entered into the model, the main independent predictors of steatosis scores in our patients with NAFLD."] Are serum pigment epithelium-derived factor levels increased in patients with biopsy-proven nonalcoholic fatty liver disease and independently associated with liver steatosis?