The expression and significance of Dickkopf-1 in epithelial ovarian carcinoma

The aim of this study was to investigate the presence and prognostic value of Dickkopf-1 (DKK1) in epithelia ovarian carcinoma. The expression of DKK1 was determined in 56 epithelial ovarian carcinoma tissues, 35 benign ovarian cystadenoma tissues, and 12 normal ovarian tissues by quantitative real-time PCR and immunohistochemistry. The DKK1 mRNA level in the carcinoma tissues was upregulated (5.5+/-2.7-fold increase) compared with that in the normal tissues (p<0.0001). The mRNA level of DKK1 in the cystadenoma tissues (1.1+/-0.4-fold increase) was not statistically different from that in the normal tissues (p=0.486). DKK1 protein expression in the carcinoma tissues was also higher (89.29%) than in cystadenoma (65.71%) and normal tissues (58.33%) (p=0.006 and p=0.009, respectively). In epithelial ovarian carcinoma, DKK1 gene and protein overexpression was associated with advanced FIGO stage (p=0.007, p=0.004) and poor differentiation grade (p=0.027, p=0.010). Elevated DKK1 protein levels in ovarian carcinoma samples were associated with a poor outcome in univariate and multivariate analysis (p<0.0001 and p<0.0001, respectively). The study indicated that DKK1 maymbe a useful prognostic and diagnostic indicator for epithelial ovarian carcinoma.