WFDC2 and ovarian cancer: In vitro and in vivo studies have shown that HE4 promotes multiple aspects of ovarian cancer aggression, including tumor growth, proliferation, metastasis, chemoresistance, and anti-estrogen resistance (Lu et al., 2012; Zhuang et al., 2013, 2014; Zhu et al., 2013, 2016; Lokich et al., 2014; Moore et al., 2014; Wang et al., 2015; Ribeiro et al., 2016; Lee et al., 2017).