Bcl-2 and Bax expression in human endometriotic and adenomyotic tissues

OBJECTIVE: To determine the Bcl-2 and Bax expressions in endometriotic and adenomyotic tissues. In addition, to evaluate the Bcl-2/Bax status during the menstrual cycle in these tissues. METHODS: A total of 56 women were retrospectively recruited from a University hospital setting. A total of 25 had endometriosis and 31 adenomyosis. Tissue samples were collected during gynaecological surgery and confirmed by histology to have endometriosis or adenomyosis. Bcl-2 and Bax expressions were investigated on 56 formalin-fixed and paraffin-embedded tissue by immunohistochemical staining and electron microscopy. RESULTS: The difference of Bcl-2-positive protein between endometriosis and adenomyosis was not significant. No significant difference was found between Bcl-2 expression and the proliferative and secretory phase of the cycle in women with endometriosis, but this comparison was highly significant (P<0.001) in women with adenomyosis. The difference of Bax-positive protein between endometriosis and adenomyosis was not significant. In addition, no significant differences were found between the various phases of the cycle. We have found a stronger inverse correlation between the expression of Bcl-2 and Bax in endometriosis than in adenomyosis. CONCLUSIONS: Our results suggest that the pathogenesis of ovarian endometriosis may be different from that of adenomyosis and the persistence of Bcl-2 and Bax expressions during both phases of the cycle in ovarian endometriotic tissues may have important implications for the survival and proliferation of the ectopic endometrial tissue.