Type 2 cadherins in the human endometrium and placenta: Their putative roles in human implantation and placentation

PROBLEM: The cadherins are a gene superfamily of calcium-dependent cell adhesion molecules. To date, the role(s) of the cadherins in human implantation remains poorly defined. METHOD OF STUDY: The spatiotemporal expression of the type 2 cadherins, known as cadherin-11 and cadherin-6, in the endometrium and placenta was examined using the reverse transcriptase-polymerase chain reaction. RESULTS: Cadherin-6 and cadherin-11 are differentially expressed in the endometrial stroma during the menstrual cycle. The switch between cadherin-6 and cadherin-11 expression in the endometrial stroma occurs during the late secretory phase. Maximum cadherin-11 mRNA levels were observed in the decidua of early pregnancy but were markedly reduced at term. In the placenta, cadherin-11 is expressed in the syncytial trophoblast and extravillous cytotrophoblast columns. However, cadherin-6 seems to be the predominant cadherin subtype present in highly invasive extravillous cytotrophoblasts. CONCLUSION: Cadherin-11 and cadherin-6 may play a central role in the formation and organization of the human endometrium and placenta.