Telomerase reverse transcriptase promoter mutation– and O6-methylguanine DNA methyltransferase promoter methylation–mediated sensitivity to temozolomide in isocitrate dehydrogenase–wild-type glioblastoma: is there a link?

Benefit from temozolomide (TMZ) chemotherapy in the treatment of isocitrate dehydrogenase (IDH)–wild-type glioblastoma is essentially limited to patients with O6-methylguanine DNA methyltransferase (MGMT) promoter–methylated tumours. Recent studies suggested that telomerase reverse transcriptase (TERT) promoter hotspot mutations may have an impact on the prognostic role of the MGMT status in patients with glioblastoma. MGMT promoter methylation and TERT promoter mutation status were retrospectively assessed in a prospective cohort of patients with IDH–wild-type glioblastoma of the German Glioma Network (GGN) (n = 298) and an independent retrospective cohort from Düsseldorf, Germany, and Zurich, Switzerland (n = 302). In the GGN cohort, but not in the Düsseldorf/Zurich cohort, TERT promoter mutation was moderately associated with inferior outcomes in patients with MGMT promoter–unmethylated tumours (hazard ratio 1.74; 95% confidence interval: 1.07–2.82; p = 0.026). TERT promoter mutations were not associated with better outcomes in patients with MGMT promoter–methylated tumours in either cohort. The two different TERT promoter hotspot mutations (C228T and C250T) were not linked to distinct outcomes. Analysis of two independent cohorts of patients with glioblastoma did not confirm previous data, suggesting that TERT promoter mutations confer an enhanced benefit from TMZ in patients with MGMT promoter–methylated glioblastoma. Thus, diagnostic testing for TERT promoter mutations may not be required for prediction of TMZ sensitivity in patients with IDH–wild-type glioblastoma. •MGMT and TERT status do not interact prognostically in IDH-wild-type glioblastoma.•TERT mutation is not linked to benefit from TMZ in IDH-wildtype glioblastoma.•C228T and C250T TERT promoter-mutant glioblastoma show similar outcome.•TERT status is not required for prognostic stratification in clinical trials.