A refined selection was achieved to obtain a highly homogeneous IDH1 wild-type GBM patient cohort divided among three groups with primary glioblastoma but with different recurrence free survival time (RFS) such as: 6 Short (S) less than 6 months, 3 Medium (M) between 16 and 23 months and 4 Long (L) over 25 months. Here, IDH1 is linked to glioblastoma.