Adjunctive role of immunohistochemical expression of Nucleostemin in differentiation of grade II and III diffuse astrocytomas

Abstract

Aims: Astrocytomas are common tumors and grade is an important parameter in determining the treatment modalities. Tumor proliferation activity should be determined for the differentiation of grades II and III tumors. In difficult cases, an auxiliary parameter is required. Nucleostemin (NS) is nucleolar Guanosine triphosphate (GTP)-binding protein 3. It has important roles in cell proliferation, cell cycle regulation, self-renewal, and apoptosis. In this study, we investigated whether the level of NS expression is different in grades II and III astrocytomas. Settings and Design: Adults diagnosed with grades II and III astrocytomas were included in the study. Material and Methods: Paraffin blocks that best reflected tumor morphology were studied via immunohistochemical staining for NS. Only nuclear staining was evaluated; cytoplasmic staining was not considered. Statistical Analysis Used: Fisher's exact test, continuity corrections, and Pearson's Chi-square tests were used in the crosstabs. The survival analysis was based on the Kaplan-Meier method. Results: Only 20% (6/30) of grade II tumors had high intensity staining, while 54,2% (13/24) of grade III tumors had high staining intensity. NS was significantly more intense in grade III tumors than grade II tumors. In cases with high NS expression, survival was significantly shorter than the cases with low expression. Conclusion: NS is significantly higher expressed in grade III tumors than grade II tumors. In difficult cases, it can be used as a useful proliferation marker in the differentiation of grades II and III astrocytomas.