Expression of pigment epithelium-derived factor decreases liver metastasis and correlates with favorable prognosis for patients with ductal pancreatic adenocarcinoma.

Pigment epithelium-derived factor (PEDF) is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we screened the expression of PEDF immunohistochemically and investigated its correlation with clinicopathological features in patients who underwent surgery for ductal pancreatic adenocarcinoma. Of the 80 patients, 22 cases (27.5%) were positive for PEDF. A significant association was found between the PEDF expression and low microvessel density (P = 0.0003). No correlation was found between PEDF expression and age, gender, depth of invasion, tumor diameter, lymphatic invasion, venous, invasion or histopathological grading. The patients in pathological stage II had a significantly higher incidence of PEDF-positive expression than those in pathological stage III or IVA (P = 0.0418). PEDF immunoreactivity was inversely associated with liver metastasis (P = 0.0422). The survival of patients that were PEDF positive was significantly longer than that of those with negative expression (P = 0.0026). Multivariate analysis using the Cox regression model indicated that PEDF-positive expression was an independent favorable prognostic factor (risk ratio, 0.394; P = 0.0016). We conclude that PEDF expression suggests a more favorable prognosis than in patients whose carcinomas lack PEDF expression.