WFDC2 and serous adenocarcinoma: The present study also observed that the level of serum HE4 was highest in serous adenocarcinoma patients and the difference compared with other types of ovarian cancer was statistically significant (p<0.01), although no statistically significant difference was observed among the mucinous adenocarcinoma and non-epithelial ovarian malignancies (Hogdall et al., 2007).