β-catenin, an epithelial-mesenchymal transition (EMT)-associated marker, is key in the progression of colorectal cancer (CRC). However, the prognostic significance of β-catenin expression in patients with CRC remains controversial. In the present study, the expression of β-catenin at the tumor invasive front and the tumor center was investigated, and the correlations amongst β-catenin differential expression patterns and the clinicopathological characteristics and prognosis of CRC patients were determined. In total, 181 patients that were diagnosed with CRC (as determined by histopathological evaluation) and subjected to surgical resection at the First Hospital of China Medical University between 2000 and 2001 were examined, and CRC specimens were obtained. Immunohistochemical (IHC) staining of β-catenin was performed for each specimen. The nuclear β-catenin expression levels were identified to be significantly lower in the tumor center than at the tumor invasive front (immunoreactivity score, 0.05±0.303 versus 2.18±3.917; P<0.001). The presence of nuclear β-catenin overexpression at the tumor invasive front was found to be correlated with the tumor, node, metastasis stage (P=0.020), lymph node metastasis (P=0.016) and histological differentiation (P=0.006). Survival analysis revealed that reduced membranous expression levels and increased nuclear expression levels of β-catenin were statistically significantly associated with poor survival times. Furthermore, differential β-catenin expression levels were associated with aggressive morphological features, EMT and a poor prognosis in CRC. Therefore, IHC analysis of β-catenin is considered to be a useful marker to predict the prognosis in patients with CRC.
Keywords: colorectal cancer; epithelial-mesenchymal transition; invasive front; tumor budding; β-catenin.