Immunohistochemical Expression of E-cadherin and β-catenin in the Normal and Malignant Human Endometrium: An Inverse Correlation Between E-cadherin and Nuclear β-catenin Expression

Abstract

Background: The E-cadherin/β-catenin complex plays a crucial role in epithelial cell-cell adhesion and in the maintenance of tissue architecture. We previously reported aberrant expression of β-catenin in endometrial carcinomas. However, the expression and correlation of E-cadherin and β-catenin in normal and malignant endometrial tissues are not fully understood. Materials and Methods: Immunohistochemical expression of E-cadherin and β-catenin was detected in 30 cases of normal endometrium and 73 cases of endometrial carcinoma. Results: In the normal endometrium, the expression of E-cadherin and cytoplasmic β-catenin in glandular cells was predominantly observed in the proliferative phase, and decreased in the secretory phase. In endometrial carcinomas, the expression of E-cadherin and cytoplasmic β-catenin decreased compared to that in the normal proliferative endometrial glands. The expression of E-cadherin and cytoplasmic β-catenin tended to be reduced in histologically high-grade tumors compared to low-grade tumors. Nuclear expression of β-catenin was observed in the glandular cells in the late proliferative and early secretory phases, as well as in high-grade endometrial carcinomas. Interestingly, nuclear β-catenin expression was associated with the loss of E-cadherin expression in normal and carcinoma cells, indicating an inverse correlation. Conclusion: The cyclic expression of E-cadherin and β-catenin in the normal endometrium suggests that the adhesion complex may act to maintain the endometrial architectures. In addition, nuclear β-catenin expression associated with loss of E-cadherin expression may be involved in the acquisition of aggressive biological behavior, especially in high-grade tumors.