Low Expression of IGFBP7 is Associated with Poor Outcome of Pancreatic Ductal Adenocarcinoma

Insulin-like growth factor binding protein 7(IGFBP7) has been implicated as a potential tumor suppressor in various human cancers, although the role of IGFBP7 in pancreatic ductal adenocarcinoma (PDAC) is still unknown. We investigated the expression pattern and clinical significance of IGFBP7 in human PDAC. IGFBP7 expression was evaluated by immunohistochemistry in 190 patients with PDAC who underwent surgical tumor resection. Expression of IGFBP7 was correlated with that of p53 and Ki-67, clinicopathologic features. We also evaluated overall survival (OS) according to expression of IGFBP7 by Kaplan-Meier and Cox regression analyses. IGFBP7 expression was significantly downregulated in pancreatic cancer tissues compared with adjacent normal pancreas (P < 0.001) and was inversely associated with Ki-67 expression (r = -0.284, P < 0.001). No significant relationships were found for clinicopathologic features, such as diameter of tumor, node status, grade, and stage. Importantly, low expression of IGFBP7 was associated with poor OS, and this was also significant in multivariate Cox regression analysis (hazard ratio [HR], 1.38; 95 % confidence interval [95 % CI], 1.00-1.91; P = 0.05). We demonstrate for the first time that IGFBP7 is downregulated in pancreatic cancer, and low expression of IGFBP7 is correlated with increased proliferation and poor postoperative survival. IGFBP7 may be a tumor suppressor in PDAC.