Immunohistochemical Features of O6-Methylguanine-DNA Methyltransferase Expression during Ovarian Endometriosis.

A comparative immunohistochemical study for the expression of O6-methylguanine-DNA methyltransferase (MGMT) was performed in tissues of the eutopic endometrium and ovarian endometriosis. The highest level of MGMT expression in eutopic endometrial tissue was observed in epitheliocyte nuclei during the proliferative phase. In regions of endometriosis the expression of MGMT in epitheliocyte nuclei was shown to increase during stages I and II, but decreased in stages III and IV. The progression of endometriosis was accompanied by a gradual increase of study parameters in the nuclei and cytoplasm of stromal cells. These changes reflect the impairment of DNA reparation, which probably serves as a stage in the development and progression of endometriosis.