['This study was designed to determine whether serum HE4 is an independent prognostic factor in ovarian cancer patients.', 'We measured HE4 in pretreatment serum samples from 80 women with epithelial ovarian cancer, using an enzyme-linked immunosorbent assay. The results were correlated with clinical data.', 'The median serum HE4 level in ovarian cancer patients was 98.7 (range, 80.3-222.8) pg/ml. Elevated serum HE4 levels before therapy significantly correlated with a poorer progression free survival (log-rank test, P = 0.017). Multivariate analysis revealed serum HE4 to be an independent prognostic factor for progression-free survival (P = 0.036). In multivariate regression analysis, high serum HE4 levels significantly correlated with high tumor grade and serous histology (P = 0.004 and 0.017). In addition, high serum HE4 levels were significantly associated with residual tumor size and operative time (P = 0.003 and 0.033).'] Is serum HE4 level an independent prognostic factor in epithelial ovarian cancer?