Wnt/beta-Catenin pathway in human glioma: expression patternand clinical/prognostic correlations

Gliomas are the most common primary intracranial tumors. Understanding the molecular basis of gliomas’ progression is required to develop more effective therapies. The Wnt/b-catenin signaling cascade is an important signal transduction pathway in human cancers. Although, overactivation of this pathway is a hallmark of several forms of cancer, little is known about its role in human gliomas. Here, we aimed to determine the clinical significance of Wnt/b-catenin pathway components in gliomas. Immunohistochemical staining was performed to detect the expression patterns of Wnt1, b-catenin and Cyclin D1 in the biopsies from 96 patients with primary gliomas. Kaplan–Meier survival and Cox regression analyses were performed to evaluate the prognosis of patients. Cytoplasmic staining pattern of Wnt1, membranous, cytoplasmic and nuclear accumulation of b-catenin, and nuclear localization of Cyclin D1 were demonstrated by immunohistochemical staining. The Wnt1 expression significantly correlated with the expression of Cyclin D1 (P\0.0001). The ratio of tumors with a cytoplasmic– nuclear pattern or a cytoplasmic pattern of b-catenin was significantly higher in Wnt1-positive (P\0.01) and Cyclin D1-positive (P\0.01) tumors than in Wnt1-negative and Cyclin D1-negative tumors, respectively. The protein expression levels of Wnt1, b-catenin and Cyclin D1 were all positively correlated with the Karnofsky performance scale (KPS) score and World Health Organization (WHO) grades of patients with gliomas. Furthermore, Wnt1, cytoplasmic–nuclear b-catenin and Cyclin D1 status were all the independent prognostic factors for glioma patients (P = 0.01, 0.007 and 0.005, respectively). These results provide convincing evidence that the Wnt/b-catenin pathway correlated closely with the progression of gliomas and might be a novel prognostic marker for this neoplasm.