Expression of Fas and Fas ligand in eutopic and ectopic endometrium of women with endometriosis

Objective: To investigate the effect of Fas/ Fas ligand expression on the pathogenesis of endometriosis( EM ). Methods: Immunohistochemistry was used to assess the expression of Fas and Fas ligand (FasL) in ectopic and eutopic endometrium from patients with EM and those from controls. Results: Eutopic endometrium showed a cyclic change in correlation with the menstrual cycle both in patients with EM and in controls, with Fas/FasL staining found to be increased in secretory phase compared with those in proliferative phase. Although no difference was found between patients with EM and control in their Fas/FasL expression in proliferative phase, there was a decreased level of Fas/ FasL expression in secretory endometria of patients with EM . Notably, expression of the two parameters in ectopic endometrium was observed to be quite low. Conclusion:The low level of Fas and FasL expression in secretory eutopic endometrium and in ectopic endometrium may participate in the ectopic transplantation of endometriosis.