Expression and localization of E-cadherin and β-catenin in uterine carcinosarcoma

This study was designed to analyze the subcellular localization of E-cadherin and β-catenin both of which play a critical role in cell-cell adhesion in uterine carcinosarcoma (UCS). We performed an immunohistochemical reaction analysis of the subcellular localization of E-cadherin and β-catenin proteins in 46 cases of UCSs consisting of 28 UCSs with heterologous sarcoma and 18 UCSs with homologous sarcoma and compared their clinicopathological features. In most UCSs, membranous expression of E-cadherin and β-catenin was completely lost in sarcomatous components, but it was preserved in carcinomatous components. Nuclear β-catenin expression was observed significantly more frequently in sarcomatous components (31/46, 67.4%) than in carcinomatous components (22/46, 47.8%; P=0.0025). In sarcomatous components, nuclear β-catenin expression was found significantly more frequently in heterologous sarcoma (23/28, 82.1%) than in homologous sarcoma (8/18, 44.4%; P=0.0279). The stage was the only independent prognostic significant factor. These results suggest that reduced membranous expression of E-cadherin and β-catenin may contribute to the biphasic morphology of UCS. Furthermore, although the precise mechanism is unclear, nuclear β-catenin expression in sarcomatous components may also be associated with biphasic morphology and heterologous sarcomatous differentiation.