Down-expression of F box only protein 8 correlates with tumor grade and poor prognosis in human glioma.

F box only protein 8 (FBX8) is a novel component of F-box proteins which involved in the ubiquitin-dependent proteolytic pathway. Recent studies have revealed that FBX8 was unregulated in tumor cells and was closely associated with tumor progression and metastasis of other cancer, but little research has been done yet to test its usefulness as a prognostic marker in human glioma. In the present study, we investigated the expression of FBX8 in glioma tissues using immunohistochemical analysis and evaluated its prognostic significance in glioma. We found that 44/77 (57.14%) gilomas had positive expression of FBX8, while 65/77 (84.42%) normal brain tissue had positive expression of FBX8. The expression level of FBX8 was remarkably down-regulated in glioma tissues compared with normal brain tissues (P < 0.001). The down-expression of FBX8 in tumor cells was strongly correlated with tumor grade of patients with glioma (P < 0.05). Patients with lower expression of FBX8 protein had shorter overall survival time than those with higher level expression of FBX8 (P < 0.05). Multivariate analysis showed that FBX8 down-expression was an independent prognostic indicator for glioma patient's survival. Our results suggest that a potential application of FBX8 in prognosis prediction and therapeutic application in glioma.