Expression and prognostic significance of epithelial-mesenchymal transition-related markers and phenotype in serous ovarian cancer.

The epithelial-mesenchymal transition (EMT) is known to be associated with carcinoma invasion and metastasis. Previous studies have demonstrated that the expression of EMT-related proteins in carcinoma cells in many organs is associated with a higher histologic grade and a poor prognosis. However, the clinical significance of EMT in ovarian cancers is controversial. Formalin-fixed and paraffin-embedded tumor samples of 198 high-grade serous carcinomas (HGSCs) and 13 serous borderline tumors or low-grade serous carcinomas (SBT/LGSCs) of the ovary were analyzed. EMT phenotype marker expression, including claudin 4, E-cadherin, N-cadherin, α-smooth muscle actin (α-SMA) and vimentin, and EMT related transition factor expression, including paired-related homeobox 1 (PRRX1), SLUG, SNAI1, and TWIST1, were evaluated by immunohistochemistry. EMT phenotype was classified into three groups including complete EMT phenotype, incomplete EMT phenotype, and epithelial phenotype according to epithelial and mesenchymal marker expression. EMT phenotypes varied in HGSC (Complete phenotype, 32.3%; Incomplete phenotype, 42.9%; epithelial phenotype, 24.7%) compared with SBT/LGSC. EMT phenotype and each EMT phenotype markers were not significantly associated with patient survival of HGSCs in multivariate analysis. However transition factor, SLUG expression, correlated with advanced disease and SLUG expression was an independent predictor of poor overall survival in HGSC. EMT related transition factor expression like SLUG is more important in association with clinical outcome than EMT phenotype itself in HGSC.