A combination between CA-125 and HE4 has also been reported in a study by Feng et al., who found that the levels of pre-operative CA-125 ≥ 313,6 U/mL and HE4 ≥ 777,1 pmol/L increased the occurrence of suboptimum cytoreduction in the advanced ovarian cancer [14]. This evidence concerns the gene WFDC2 and ovarian cancer.