Suggested GBM genetic biomarkers of the efficacy of TMZ (35) include isocitrate dehydrogenase 1 and 2 (IDH1/2) gene mutations and 1p and 19q chromosomal co-deletions (36, 37) which have acquired clinical relevance because of their diagnostic, prognostic, and sometimes predictive value even though they are still related to the status of genome methylation (9, 11, 12). Here, IDH1 is linked to glioblastoma.