Identification of the cadherin subtypes present in the human peritoneum and endometriotic lesions: potential role for P-cadherin in the development of endometriosis.

Endometriosis is defined as endometrial tissue outside of the uterine cavity. The pathogenesis of this common disease remains poorly understood. However, the implantation and invasion of the viable cells from retrograde menstruation into the peritoneum is a widely accepted theory. To date, the mechanisms by which cell adhesion molecules mediate the development of human endometriosis remain unclear. Cadherins are a family of cell adhesion molecules that mediate cell-cell adhesion in a homophilic manner. In this study, the cadherins present in the peritoneum and endometriotic lesions were identified by RT-PCR using degenerate primers. In addition, differences in the levels of the cadherin mRNA transcripts present in eutopic endometrium and endometriotic lesions of the same patients were then compared by semiquantitative RT-PCR. Multiple cadherins were detected in the peritoneum and endometriotic lesions. Of these, P-cadherin appears to be the predominant cadherin subtype present in the peritoneum. Similarly, P-cadherin mRNA levels in endometriotic lesions were significantly greater than those observed in the corresponding eutopic endometrium. The expression of P-cadherin in both the human peritoneum and endometriotic lesions suggests that this cell adhesion molecule may play a central role in the development of endometriosis by mediating endometrial-peritoneal cell interactions in a homophilic manner.