Apoptosis and bcl-2 expression in normal human endometrium, endometriosis and adenomyosis

Apoptosis has been implicated in the pathogenesis of several diseases and i s partly regulated by bcl-2, which blocks the apoptotic pathway and promote s cell survival, Apoptosis and bcl-2 expression were examined in paired eut opic and ectopic endometrium from women with endometriosis (n = 30 samples) or adenomyosis (a 15 samples) and compared with control endometrium (n = 3 0 samples). Apoptotic cells were detected using the dUTP nick-end labelling (TUNEL) assay for DNA fragmentation; bcl-2 expression was demonstrated wit h a streptavidin-biotin peroxidase immunohistochemical technique. Apoptotic cells were rare in eutopic, ectopic and control endometrium; there were no significant differences between subject groups nor between eutopic and ect opic endometrium, Stromal bcl-2 expression increased in the late secretory phase in control and eutopic endometriun in endometriosis; double labelling studies revealed that most stromal bcl-2+ cells were leukocytes. Stromal b cl-2 expression in endometriotic foci was significantly increased compared with the paired eutopic endometrium, did not vary with menstrual cycle and included a significant population of non-leukocytic bcl-2+ stromal cells, I n contrast, stromal bcl-2 expression in adenomyosis remained at low levels and did not show significant cyclical variation. Glandular epithelial bcl-2 expression also varied with menstrual cycle phase and peaked in the prolif erative phase; in contrast, surface epithelial bcl-2 expression increased i n the late secretory phase, Elevated stromal bcl-2 expression in ovarian en dometriotic lesions could have implications for the growth and survival of ectopic endometrial tissue at these sites.