Background: None of the existing theories provides a satisfactory explanation of the development of endometriosis. One hypothesis that may lead to further clarification is that the expression of specific proteins of human endogenous retroviruses (HERVs) might influence the development of endometriosis lesions. Such endogenous retroviral proteins include syncytin, coded by HERV-W, which is associated with the physiological development of the placenta during pregnancy. This study investigated the influence of HERV-W gene expression in endometriosis foci (EM) quantitatively at the RNA level.
Materials and methods: Specific RNA expression of syncytin (HERV-W) was investigated in various endometrial tissues from 42 patients (with normal endometrium, postmenopausal endometrium, EM, and endometrial carcinoma). RNA was isolated from the tissue samples and transcribed into DNA using reverse transcriptase polymerase chain reaction. The resulting DNA fragments were analyzed using agarose gel electrophoresis and assessed quantitatively.
Results: Normalized syncytin expression was low in EM. In Histologically normal endometrium from endometriosis patients, the expression of normalized syncytin was seven times higher in comparison with the histologically normal endometrium in the control group.
Conclusions: HERV-W syncytin expression apparently does not play a role in EM. However, it may possibly influence the development of endometriosis because of increased expression in normal endometrium in endometriosis patients.