Alteration of many genes have been found to be implicated in pathogenesis of GB, hence they may play an important role in predicting prognosis and response to treatment strategies . In the current study, the role of IDH1 gene mutation and MGMT promoter methylation status were investigated among Egyptian GB patients as compared to a group of NND. Among the investigated groups no significant difference was reported between their genders however significant difference was reported among their ages as all NND were below 60 years. This result emphasizes the relation between the increase of GB among elderly which agree with previous reported studies [22, 23] which may be attributed to the fact that aging may gradually suppresses immunosurveillance and hence contributes to GB cell initiation and/or outgrowth .
Sanger sequencing is considered the "gold standard" for detection of IDH1 mutations because of its high specificity and low false positive results but with some drawbacks as low sensitivity, consumes time and high-quality tissue samples to perform the reaction in addition needs manual interpretation . As it is significant to detect the occurrence of IDH1 mutations in a rapid method thus patients can gain the advantage from targeted therapies, Therefore authors detected IDH1 mutation using TaqMan™ competitive allele-specific probes (castPCR™) which has high sensitivity over Sanger sequencing (0.1% versus 10–25%, respectively)  and high specificity as minimal quantities of mutated DNA in a sample that have large quantities of normal wild-type DNA  since this technique uses oligonucleotides for the mutated allele so as to repress the normal allele . Accordingly, in the current studyIDH1 mutation was not detect among patients with NND 0 out of 20 individuals (0%), these results were agreed with previously reported data  who reported that detection of IDH1 mutation points to the presence of glioma and it cannot be attributed to non-neoplastic diseases. For GB cases IDH1 mutation was detected in 15 out of 58 (25.9%). These results are in concordance with Kalkan and his colleagues  who reported the presence of IDH1 mutations in 12.5% primary GB cases which reveal that it is an early consequence in tumor genesis and this due to the fact that mutated IDH1 reduce the action of NADPH which is important for cellular protection against oxidative stress giving rise to tumor genesis because of oxidative DNA damage .
Methylation status of MGMT is among the most studied molecular biomarkers in neuro-oncology because of its influence in therapeutic management of glioblastoma, thus its detection has been reported using different techniques . However, debate remains about the most appropriate technique to be used, in the current study authors assessed methylation status using restriction enzyme that cut the unmethylated regions and hence the detected will be the methylated (REF). Although it was previously reported in several neuro-oncological centers as 10% as the biological cutoff , others reported that precise cutoff value might reflect their response to treatment . In the current study as for the first time NND were included, the ROC was plotted between both groups as considering NND as reference (control) group hence the best cutoff point was 66% methylation (< 66% as low-moderate methylation, ≥ 66% as highly methylated). By using this methylation cutoff, currently studied groups reported all NND patients with high MGMT methylation as compared to GB cases as 51.9% were high MGMT methylation. Methylation of NND patients could be attributed to the previously reported findings of Teuber-Hanselmann and his colleagues that MGMT hypermethylation arises in chronic neurological diseases that are not strictly associated to distinctive pathogens, oncogenic viruses or neoplasms but that lead to destruction of the myelin sheath in several ways .
Among the GB cases; those reported IDH1 mutation were of younger age (less than 60 years) than those with older ages; these results agreed with previously reported study by Kalkan and his colleagues , for MGMT methylation; significant levels were reached with factors like tumor size and tumor location which agreed with previous reports [34, 35] as GB patients with tumor size less than 5cm reported high methylation than others with mass more than 5cm, moreover it is generally recognized that tumor location, as significant image feature related to genetic features, is associated with patient prognosis . Also, both IDH1 mutation and MGMT methylation were reported at significant levels in GB patients with ECGO < 2 which may indicate their usefulness as prognostication markers among GB patients.
After patients were treated with standard of care treatment strategy, they were followed-up for median 10 months, GBM patients with IDH1 mutations reported better PFS and OS than those with IDH1 wild type. A finding that agreed with previously reported study  that IDH1 mutations can be used as a prognostic marker for primary GB patients since it is primary event in tumorigenesis. Regarding GB patients with MGMT high methylation reported better PFD and OS as compared to those with low-moderate methylation, these results in concordance with .When GB patients with both IDH1 mutations and MGMT high methylation were considered, our results emphasized best PFS (20 months ) and OS (25 months) indicating that detection of IDH1 mutation combined with MGMT methylation is a better prognostic marker and estimates response of GB patients to treatment than any of them alone this was agreed with previously reported finding  thus using both combined markers for predicting response to treatment and predicting survival pattern is obviously advised than using any of them alone.