Evaluation of β-catenin expression in muscle-invasive urothelial bladder carcinoma

Objectives This study aimed at evaluation of the expression of β-catenin in muscle-invasive urothelial bladder carcinoma and its correlation with other clinicopathological parameters of prognostic importance. Background β-Catenin is a protein that is encoded by the CTNNB1 gene that can function as an oncogene. Activation of the Wnt/β-catenin signaling pathway by aberrant accumulation of stabilized β-catenin contributes to the progression of several human cancers. Therefore, inhibition of the Wnt pathway may have a major therapeutic potential. Patients and methods This study was conducted as a retrospective study at Urology and Pathology Departments, Faculty of Medicine, Menoufia University, during the period between May 2011 and May 2013. A total of 40 patients were included and divided into two groups. The first one included 10 patients with chronic nonspecific cystitis as a control group and the second one included 30 patients with muscle-invasive urothelial bladder carcinoma who underwent radical cystectomy. The pathological blocks of both groups were investigated for the expression of β-catenin using immunohistochemical staining. Results β-Catenin expression was noticed in 100% (30 cases) of muscle-invasive bladder carcinoma and in 70% (seven cases) of nonmalignant cases. In the malignant group, 26 (87%) cases showed nucleocytoplasmic expression and four (13%) cases showed membranous expression only. There was a significant correlation between nucleocytoplasmic localization of β-catenin and some pathological parameters such as tumor grade, stage, and mitosis. Furthermore, the study showed statistically significant correlation between intensity of β-catenin expression and tumor grade, stage, lymph node metastasis, vascular and perineural invasion, mitosis, and microvessel density. Conclusion Nucleocytoplasmic expression of β-catenin and high intensity of its expression was associated with poor prognostic parameters.