Analysis of oncogene gli1 protein expression levels between differing grades of astrocytoma

Abstract

Background: Aberrant expression of oncogene GLI1 has been linked to malignancies in many types of tissues including brain, pancreas, skin and breast[1-4]. It has been found that GLI1 expression is important for tumor progression and has been linked to tumor grade[1,5-7]. In this study, GLI1 expression has been analyzed in different malignancy grade astrocytomas. Materials and Methods: GLI1 protein expression was evaluated in 87 clinical tumor samples by using Western blot analysis. Associations between GLI1 expression and tumor grade were analyzed by applying the Mann-Whitney or Kruskal-Wallis tests. Kaplan-Meier survival analysis was performed to evaluate the prognosis of patients. Results: Western blot analysis did not show statistically significant correlation between GLI1 protein expression and astrocytoma tumor grade (P = 0.294). Kaplan-Meier survival also did not show correlation between survival rates and GLI1 expression (P = 0.081). Our results show that GLI1 protein expression levels in astrocytomas have higher variability than previously shown. Conclusion: Our results indicate that GLI1 protein expression is not an absolute requirement for the process of gliomagenesis. Yet, the relatively high (up to 52%) occurrence of GLI1 expression in astrocytomas suggest the need for further analysis on the involvement of GLI1-mediated Hedgehog signaling pathway in glioma tumorogenesis.