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. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.