Expression of EIF-5A2 gene in ovarian carcinoma and its clinical significance

Abstract

Objective: To investigate the expression and amplification of eukaryotic translation initiation factor 5A2 (EIF-5A2) gene in epithelial tumor of the ovary and its clinical significance. Methods: Immunohistochemistry and fluorescence in situ hybridization, in combination with tissue microarray, were used to examine the protein expression and amplification of EIF-5A2 in 50 ovarian adenomas, 50 borderline tumors of the ovary and 150 ovarian carcinomas to evaluate the potential associations between EIF-5A2 expression and patient's clinico-pathologic parameters in ovarian carcinoma cohorts. Results: In the immunohistochemical assay, over-expression of EIF-5A2 protein occurred in 6.4% of benign ovarian adenomas, 28.3% borderline tumors and 56.6% ovarian carcinomas. In ovarian carcinomas, there was a significant correlation in EIF-5A2 expression, Silverberg's grading and FIGO staging (P<0.05), in which the over-expression of EIF-5A2 was observed in 70.0% of high-grade (G3) carcinomas, with the positive rate significantly higher than that in the G1/G2 carcinomas (49.5%). This over-expression also occurred in 65.6% of the carcinomas with late clinical stages (FIGO stage III/IV), with a significantly higher positive rate compared to that in the tumors with FIGO stage I/II (38.3%). Furthermore, there was a significant positive correlation between EIF-5A2 over-expression and cell proliferation (the levels of Ki-67 expression) in our ovarian carcinomas (P<0.01), in which higher expression of Ki-67 was found in the majority of carcinomas with over-expression of EIF-5A2 (72.8%), while lower expression of Ki-67 was seen in the majority of carcinomas with normal expression of EIF-5A2 (66.1%). It was shown by fluorescence in situ hybridization assay that amplification of EIF-5A2 gene was present in only 13.8% of the ovarian carcinomas. EIF-5A2 amplification was not observed in the borderline or the benign ovarian tumors. Conclusion: Over-expression of EIF-5A2 protein may possibly, at least in part, play an important role in the tumorigenesis of epithelial tumors of the ovary through its effect of promoting cell proliferation. Moreover, it is in close correlation with the malignant histological phenotype and/or invasive process of ovarian carcinomas.