Background: The immediate early response gene X-1 (IEX-1) is a stress-inducible protein that is involved in the regulation of cell proliferation and apoptosis. The aim of this study was to evaluate the prognostic significance of IEX-1 expression in pancreatic cancer.
Methods: IEX-1 protein expression was examined on paraffin-embedded specimens from 78 patients with pancreatic ductal adenocarcinoma using immunohistochemistry. The relationships between the IEX-1 expression and other clinicopathological parameters and patient survival were evaluated. A similar analysis was conducted in a subgroup of 48 patients, who underwent a macroscopically curative resection with detailed information on the pathological findings.
Results: Among 78 pancreatic cancer patients, 41 patients (53%) were positive for IEX-1 staining. In a multivariate analysis, curative operation (P < .001), pathological stage I-III (P = .001), and positive IEX-1 expression (P = .002) were significantly favorable factors for survival. In a subgroup of 48 patients undergoing a macroscopically curative surgery, IEX-1 expression was positive in 28 patients (58%). A significant negative correlation was observed between the IEX-1 expression and serosal (P = .032) or arterial (P = .040) invasion of tumors. A multivariate analysis demonstrated limited local invasion (pT1-3, P = .021), negative lymph node involvement (pN0, P < .001), and positive IEX-1 expression (P = .004) to be significantly favorable factors for survival.
Conclusions: The positive IEX-1 expression in tumor tissues may be associated with a better prognosis in pancreatic cancer. An immunohistochemical assessment of IEX-1 expression may therefore be helpful for predicting patient prognosis in this disease.