β-catenin and E-cadherin expression patterns in high-grade endometrial carcinoma are associated with histological subtype

Both β-catenin and E-cadherin are epithelial cell adhesion molecules. In addition, β-catenin is an important element of the Wnt signal transduction pathway, which has been implicated in embryogenesis and carcinogenesis, including the development of endometrial and ovaran endometrioid carcinomas. We hypothesized that the expression pattern of these two adhesion molecules may depend upon the histological subtype of endometrial carcinomas. Therefore, we compared the immunohistochemical expression of β-catenin and E-cadherin in a set of uterine adenocarcinomas matched for high histologic grade, that is, poorly differentiated (International Federation of Gynecology and Obstetric [FIGO] Grade III) uterine endometrioid carcinomas and uterine serous carcinomas. Seventeen FIGO Grade III endometrioid adenocarcinomas and 17 serous carcinomas were evaluated histologically and immunohistochemically with commercially available monoclonal antibodies against β-catenin and E-cadherin. Nuclear expression of β-catenin was observed in 8 of 17 (47%) endometrioid adenocarcinomas but in none of the serous carcinomas (P =.003). Moderate or strong E-cadherin expression was identified in 7 of 17 (41%) serous carcinomas as opposed to in only 1 of 17 (6%) endometrioid adenocarcinomas (P =.02). The majority of endometrioid adenocarcinomas showed strong β-catenin expression coupled with weak E-cadherin expression; serous carcinomas did not exhibit a comparable trend. Our results indicate that the expression of β-catenin and E-cadherin in high-grade endometrial cancers is strongly associated with histological subtype. These data provide further support for the distinct molecular profiles of endometrioid adenocarcinoma and serous carcinoma. Notably, differences in cell adhesion molecule expression could account for variations in patterns of tumor dissemination. The immunohistochemical staining pattern may also be useful for diagnostic purposes.