MUC16 and ovarian cancer: CA125 also downregulated the expression of DKK1 in vitro. To address the relationship between the CA125-mediated decrease in DKK1 expression and the enhanced migration of cells, we transfected the pEGFP-N1-DKK1 vector and siDKK1 into ovarian cancer cells to overexpress and knock down DKK1.