CD24 and Nanog expression in Stem Cells in Glioblastoma: Correlation with Response to Chemoradiation and Overall Survival

Background and aim: Glioblastoma (GBM) is one of the most common and aggressive brain tumors with a median survival of 12-14 months. The aim of present study was to evaluate the gene expression profile of stem cell markers Nanog and CD24 in GBM and to determine its relationship to outcome in terms of treatment response and overall survival. Material and methods: This was a retrospective as well as retrospective study which included 51 histologically confirmed cases of GBM. Expression of CD24, and Nanog was evaluated by RT-PCR. Control tissue included debrided brain tissue from open head injury cases. All cases of GBM underwent total surgical resection and subsequently chemotherapy. Immediate treatment response was evaluated at 3 months using Response Evaluation Criteria In Solid Tumors (RECIST) guidelines and overall survival was measured at 36 months. Result: As compared to control gene, expression of CD24 and Nanog was seen to be unregulated to 24.5% and 31.7% respectively. However, the difference in mean expression of cases and controls was not statistically significant. Correlation between expressions of these two markers was also not statistically significant. On univariate cox regression analysis, cases with >2 fold expression of CD24 and Nanog had significantly poor survival as compared to those with 2 fold CD24 expression had a statistically significant correlation with poor survival. Conclusion: An overexpression of CD24 by more than two fold was associated with poor overall survival in GBM. Poor survival may be related to increased "stemness" of tumour cells. Targeted therapy inclusive of drugs targeting stem cells directly or indirectly may be a promising therapeutic option.