Association between increased serum GP88 (progranulin) concentrations and prognosis in patients with malignant lymphomas

Background GP88 (progranulin; PGRN) is a secreted 88 kDa glycosylated protein, with important functions, including inflammation and tumorigenesis. We assessed the significance of GP88 expression in survival outcomes of patients with malignant lymphoma (ML). Methods Serum samples from 254 previously untreated ML patients were examined to measure GP88 concentrations using a sandwich human GP88 ELISA kit. Immunohistochemical analyses were performed to examine GP88 tumor tissue expression. Results The median serum GP88 concentration of ML patients was 91.3 ng/ml, and was significantly higher than that of the control group (median, 57.7 ng/ml) (p < 0.0001). Association between GP88 serum concentrations and overall survival (OS) was examined in patients with diffuse large B cell lymphoma (DLBCL) who had been stratified based on their serum GP88 concentrations. Kaplan Meier survival analysis showed that patients with serum GP88 concentrations of ≤ 116 and > 116 ng/ml, had 5-y OS rates of 70% and 50%, respectively (p = 0.02). The immunohistochemical analyses of GP88 tumor expression revealed that DLBCL patients had lymphoma cells that were positive for GP88. Conclusions High serum GP88 concentrations are associated with poor prognosis in patients with DLBCL.