Tenascin is differentially expressed in endometrium and endometriosis.

Endometriosis is characterized by the presence of functional endometrial tissue outside the uterine cavity, most commonly on the ovary and peritoneum. The aetiology of endometriosis is not understood, although the adhesion of endometrial cells to the extracellular matrix (ECM) would be expected to play a central role in its pathogenesis. The expression of ECM molecules in endometrium and in endometriosis has been investigated using immunohistochemistry and western blotting techniques. The ECM components collagen IV, laminin, vitronectin, and fibronectin had a similar pattern of expression throughout the menstrual cycle in endometrium and endometriosis. Expression of tenascin was elevated in the stroma of the functionalis region of the endometrium during the proliferative stage of the menstrual cycle and in endometriosis. Tenascin expression in endometriosis was not modulated according to the stage of the menstrual cycle. It is concluded that expression of tenascin is strictly regulated in endometrium and may be important in endometrial regeneration and in the pathogenesis of endometriosis.