Integrins alpha 3 and alpha 6 are differentially expressed in endometrium and endometriosis.

The expression of integrin subunits has been investigated in the stroma and epithelium of eutopic and ectopic endometrial tissues, using immunohistochemistry and fluorescently activated cell-sorting techniques. Integrin subunits exhibited tissue-specific expression in both eutopic and ectopic endometrium. Integrin alpha 3 subunit was up-regulated in ectopic endometrium compared with the eutopic counterpart, whereas alpha 6 integrin subunit was down-regulated in the ectopic tissues. Cycle stage-dependent expression of alpha v and beta 3, observed in eutopic endometrium, was absent in the ectopic counterpart. It is concluded that the development and regeneration of the endometrium involve complex integrin-ligand interactions and that regulation of specific adhesive events is lost in endometriosis.