Expression of E-cadherin and β-catenin is Altered at Tumor Budding Sites, Whose Number is Associated with the Progression of Colorectal Carcinoma

Abstract

Background : Tumor budding is present in the stroma at the invasive margin of colorectal carcinomas (CRC). The disintegration of cell adhesion molecules is closely related to this process. This study investigated the role of tumor budding in the progression of CRC, and compared the expression of b-catenin and E-cadherin between tumor budding and tumor center to determine whether epithelial-to-mesenchymal transitions (EMTs) occur in tumor budding. Methods : The number of tumor budding (NTB) instances was determined in 58 cases of CRC, and immunoreactivities of E-cadherin and b-catenin were compared at the tumor center and at the tumor budding site. Immunohistochemical staining for vimentin was also done. Results : Tumor budding was seen in 52 tumors (90%). There were significant associations between NTB and cliniopathologic parameters such as tumor depth, nodal metastasis and clinical stage. Expression of cytoplasmic and nuclear b-catenin were significantly higher at tumor budding sites than in the tumor center. In contrast, expression of membranous and cytoplasmic E-cadherin were significantly higher in the tumor center than at the tumor budding sites. Vimentin was expressed at tumor budding foci of only 2 cases (3%). Conclusions : This study suggests that EMT occurs at tumor budding, and that NTB may be a good marker for predicting a poor prognosis in CRC.