Loss of Beta-Catenin Expression in Metastatic Gastric Cancer

Purpose: Beta-catenin (β-catenin) participates in intercellular adhesion and is an integral part of the Wnt signaling pathway. The role of β-catenin in the pathogenesis of gastric cancer and its metastasis is largely unknown. Patients and Methods: Immunohistochemistry and Western blot analysis were used to analyze the expression of β-catenin in 87 human gastric cancers, in metastasis and cancer cell lines. The β-catenin and the adenomatous polyposis coli (APC) genes were analyzed for gene mutations. Furthermore, methylation of the β-catenin promoter in cell lines was assessed by treatment with 5′-azadeoxycytidine and sodium bisulfite genomic sequencing. Results: β-Catenin expression was present at either the cell membrane or the cytoplasm in 34 of 75 primary gastric cancers. Expression of β-catenin was significantly more frequent in intestinal-type (P = .0049) and well-differentiated gastric cancers (P < .001). There were no quantitative differences between gastric cancers and the nonmalignant gastric tis...