WFDC2 and neoplasm: ELISA assay was used to detect serum HE4 in 16 control serum samples and 24 tumor samples, and results showed a significant increase of HE4 in tumor serum compared with control (control, 3.58 ± 0.24 ng/mL, tumor, 4.42 ± 0.17 ng/mL; p = 0.006) (Figure 3).