Analysis of oncogene GLI1 protein expression levels between differing grades of astrocytoma

Abstract

Aberrant expression of oncogene GLI1 has been linked to malignancies in many types of tissues including brain, pancreas, skin and breast. It has been found that GLI1 expression is important for tumor progression and has been linked to tumor grade. In this study, GLI1 expression has been analyzed in different malignancy grade astrocytomas. GLI1 protein expression has been evaluated in 87 clinical tumor samples by using Western blot analysis. Associations between GLI1 expression and tumor grade were analyzed by applying Mann-Whitney or Kruskal-Wallis tests. KaplanMeier survival analysis was performed to evaluate the prognosis of patients. 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. Our results indicate that GLI1 protein expression is not an absolute requirement for the process of gliomagenesis. Yet, a relatively high (52%) occurrence of GLI1 expression in astrocytomas suggests the need for further analysis on the involvement of GLI1-mediated Hedgehog signaling pathway in glioma tumorogenesis.