WFDC2 and ovarian cancer: The dependence of WFDC2 expression on estrogen activity led us to study whether the proliferative growth of ovarian cancer cells induced by E2 was mediated by WFDC2. The sequence 209 shRNA, which was shown to effectively knock down the expression of WFDC2 in SKOV3 cells [12], was inserted into the retroviral vector and transduced into estrogen-sensitive HO8910 cells to produce the stable WFDC2 knockdown cell line (HO8910-209) (Additional file 1: Figure S1).