HE4 is a novel tissue marker for therapy response and progestin resistance in medium- and low-risk endometrial hyperplasia.

The aim of the present study was to investigate whether changes in the tissue expression of human epididymis-specific protein 4 (HE4) could predict therapy resistance and relapse after progestin hormone therapy for medium- and low-risk endometrial hyperplasia. Endometrial biopsies were obtained from women participating in a multicentre RCT performed according to the CONSORT guidelines; the women were randomly assigned to either LNG-IUS; 10 mg of oral medroxyprogesterone acetate (MPA) administered for 10 days per cycle; or 10 mg of oral MPA administered daily for 6 months. Of the 153 women who completed therapy, 141 had adequate material for immunohistochemistry in pre- and post-treatment biopsies. An antibody to HE4 (clone 12A2 monoclonal IgG1 antibody, Fujirebio Diagnostics, Inc.) was used for the immunohistochemical staining of the pre- and post-treatment biopsies from each participant. The expression of HE4 staining was evaluated by the histological score (H-score) using light microscopy. Changes in the expression of HE4 (H-score) during therapy were related to the therapy group (P<0.001) and therapy response (P<0.001) of the individuals but could not predict relapse (P>0.05). Changes in the intracellular bodies were shown to predict both the therapy response (P=0.038) and relapse (P=0.014). Changes in the expression of HE4 during progestin therapy regimens can predict therapy response or indicate progestin resistance for medium- and low-risk endometrial hyperplasia.