Expression of X-Linked Inhibitor of Apoptosis Protein in Human Colorectal Cancer and Its Correlation With Prognosis

Background: X-linked inhibitor of apoptosis protein (XIAP) is a member of the inhibitor of apoptosis family of proteins and deregulation of XIAP can result in tumorigenicity. The objective of this study was to evaluate the prognostic significance of XIAP expression in colorectal cancer (CRC). Methods: RT-PCR was performed to detect the expression of XIAP mRNA in CRC cells and tissues. The expression of XIAP protein in tissues was measured by immunohistochemistry. The correlation of XIAP expression with clinicopathologic factors and prognosis of CRC patients was evaluated. Results: CRC cells showed significantly higher levels of XIAP mRNA expression than normal human intestinal epithelial cell. The expression level of XIAP mRNA in CRC samples was significantly higher than that in corresponding non-tumor samples. XIAP staining was positive in the cytoplasm of CRC cells. Higher XIAP protein expression was significantly correlated with tumor differentiation (P=0.016), venous invasion (P=0.039), and Duke's staging (P=0.002). Moreover, XIAP-high group showed lower disease-free (P=0.0136) and overall survival (P=0.0084) rates than XIAP-low group. Multivariate analysis indicated that the status of XIAP expression was an independent prognostic factor for CRC (P=0.0206; HR: 2.730 95% CI: 1.226-5.445). Conclusion: The status of XIAP expression might become an independent prognostic marker for CRC. J. Surg. Oncol. 2009;100:708-712. (C) 2009 Wiley-Liss, Inc.