Co-expression of Y box-binding protein-1 and P-glycoprotein as a prognostic marker for survival in epithelial ovarian cancer

Objectives. This study aimed to observe the expressions of Y box-binding protein-1 (YB-1) and P-glycoprotein (P-gp) in primary ovarian tumor and to determine whether they act as biomarkers for survival in epithelial ovarian cancer. Methods. The expressions of YB-1 and P-gp were examined immunohistochemically in 59 patients who were treated from 1997 to 2000 at Kurume University Hospital. Samples were paraffin-embedded primary ovarian cancer tissue taken from the surgical specimens. Results. Of the 59 primary ovarian tumors examined, 32 (54.2%) and 18 (30.5%) were positive for YB-1 and P-gp, respectively. Coexpression of these two proteins was observed in 20.3% (12/59) cases. Patients showing this co-expression had a worse 3-year survival than those without co-expression (40.0% vs. 73. 1 %, P 0.0447). This co-expression significantly correlated with poor prognosis according to multivariate analysis (P = 0.0007). Conclusion. Co-expression of YB-1 and P-gp emerged as a promising relevant biomarker for unfavorable prognosis in ovarian cancer. (C) 2004 Elsevier Inc. All rights reserved.