WFDC2 and endometrial cancer: In 2011, Yang et al. [9] performed an immunohistochemical assay and enzyme-linked immunosorbent assay to determine HE4 expression in tissue and peripheral blood from 31 cases of endometrial cancer for the first time, and the results indicated that the positive expression rate of HE4 and serum level of HE4 in the malignant group were significantly higher than those in the normal endometrium group (20 cases) and the endometrial hyperplasia group (19 cases), and the difference was statistically significant.