In order to evaluate miR-181b/d exosomal expression as a prognostic biomarker, GBM patients were grouped into two specific groups: group A—GBM patients who were older than 55.3 years, had IDH1 wild-type genotype, a hypermethylated MGMT promoter, and higher than median miR-181b/d exosomal expression; group B—the same previous criteria but with a lower than median miR-181b/d exosomal expression. This evidence concerns the gene IDH1 and glioblastoma.