IDH-mutant GBMs are known to show much better prognosis than IDH-wildtype GBMs.[10] According to the WHO classification of tumors of the central nervous system published in 2016, GBM with IDH mutation is classified as a different entity from GBM with IDH-wildtype.[25] In our study, IDH mutation was examined in 42% of patients who performed immunohistochemical staining for IDH1 R132H. This evidence concerns the gene IDH1 and glioblastoma.