WFDC2 and ovarian serous carcinoma: HE4 is abnormally elevated in most serous ovarian carcinoma, endometrioid carcinoma, and clear cell carcinoma of the ovary, but low in mucinous ovarian carcinoma and other non-epithelial ovarian malignancies, and HE4 is affected by the patient's age and renal function (36, 37).