Expression of cadherins and CD44 isoforms in human endometrium and peritoneal endometriosis

Background. To evaluate (a) cadherins and CD44 expression in normal endometrium and in peritoneal endometriosis, and (b) to correlate, their expressions with clinicopathological parameters. Methods. E- and N-cadherin, CD44 isoforms, CD44v3 and CD44v6 expressions were evaluated: (a) by immunoblotting in endometrium (n = 6) and in peritoneal endometriotic samples (n = 7) and, (b) by immunohistochemistry in endometrium (n = 15) and in peritoneal endometriotic samples (n = 23). Results. By immunoblotting, endometrium expressed E- and N-cadherin, CD44 isoforms, CD44v3 and CD44v6. Similar results were observed in peritoneal endometriosis. By immunohistochemistry, in endometrium, E-cadherin was restricted to epithelial cells. Its expression remained constant throughout the menstrual cycle. N-cadherin was detected in both epithelial and stromal cells in the proliferative phase but was restricted to epithelial cells in the secretory phase. CD44 immunostaining was detected in the secretory but not in the proliferative phase. Decreased expression of E-cadherin (p < 0.01) and CD44 (p < 0.01) in epithelial cells was found in peritoneal endometriosis as compared with normal endometrium. In endometriotic stromal cells, decreased CD44 expression was found. In peritoneal endometriosis, we observed a decreased expression of E-cadherin in advanced stages of the disease (p < 0.01). Conclusion. Our results suggest that E-cadherin and CD44 proteins could be involved in the development of endometriotic lesions. Investigation of the mechanisms of altered adhesion molecule expression may contribute to the understanding of the behavior of endometriotic cells.