Aberrant Distributions and Relationships Among E-cadherin, β-catenin, and Connexin 26 and 43 in Endometrioid Adenocarcinomas

During carcinogenesis, loss of intracellular cohesion is observed among cancer cells with altered expression of such adhesion molecules as E-cadherin and beta-catenin, and aberrant expression and cellular location of intercellular gap junction proteins-connexins. The aim of this study was to evaluate immunohistochemically the expression and relationship between E-cadherin and beta-catenin, and the connexins Cx26 and Cx43 in 86 endometrioid adenocarcinomas. The aberrant cytoplasmic translocation of the studied proteins was a predominant finding, whereas only a minority of cases showed normal, nuclear beta-catenin labeling or membranous distribution of the remaining molecules. E-cadherin was positively and significantly associated with beta-catenin (P=0.001, r=0.366), as was Cx26 with Cx43 (P0.001, r=0.719), E-cadherin with Cx26 (P0.001, r=0.413), and E-cadherin and Cx43 (P0.001, r=0.434) in all cancers. A subgroup of endometrioid adenocarcinomas (FIGO IB+II) exclusively showed a positive significant association between the expression of beta-catenin and Cx26 (P=0.038, r=0.339). In addition, there were significantly more beta-catenin-positive carcinomas among superficially spreading cancers (FIGO IA) than among deeper invading neoplasms (FIGO IB+II) (P=0.056). The altered location of the studied proteins indicates impairment of their physiological functions. In particular, normal membranous distribution of E-cadherin and connexins is lost and replaced by abnormal cytoplasmic accumulation in most cancers, and thus intercellular ties are expected to be weakened and loosened as a consequence. In contrast, the lack of relationship between beta-catenin and connexins, E-cadherin seems to be closely associated with the expression of Cx26 and Cx43 in endometrioid adenocarcinomas.