Expression of serpin B5 in colorectal cancer: Its relationship with CEA expression.

Abstract

e14606 Background: Serpin B5 is a candidate tumor suppressor but its oncogenic activity has been also reported. Its function may be affected by interacting proteins. The aim of this study was to assess the relationship between serpin B5 and carcinoembryonic antigen (CEA) expressions in CRC. We also analyzed the clinicopathological significance of serpin B5 expression in colorectal cancer (CRC) patients. Methods: Two-dimensional gel electrophoresis (2-DE) analysis and matrix-associated laser desorption ionization mass spectrometry (MALDI-MS) were used to identify differentially expressing proteins according to CEA suppression. Serpin B5 and CEA expressions were evaluated by western blot and ELISA assays. Immunohistochemical expression of serpin B5 was assessed retrospectively in tissues from 377 CRC patients, and correlations between serpin B5 and clinicopathological parameters were analyzed. Results: Downregulation of serpin B5 was identified in CEA-suppressed LoVo cell line using 2-DE and MALDI-MS analyses, and further significant positive correlations between serpin B5 and CEA levels were also found in human CRC cell lines and in blood of CRC patients. Tissue expression of serpin B5 in CRC was significantly associated with serum CEA, histologic grade, stage, lymph node metastasis, liver metastasis, lymphatic and perineural invasion, and infiltrative border. High expression of serpin B5 was also associated with a reduced DFS (P = 0.001) and OS (P = 0.017). Conclusions: This is the first study describing relationship between serpin B5 and CEA expression in CRC. High expression of serpin B5 was also associated with worse prognosis in patients with CRC, and its expression may correlate with CEA levels in CRC.