MGMT and Cognitive impairment: Most clinical studies focus on investigating patients with MGMT promoter methylation (MGMT-met), with cognitive function as a secondary outcome.21 According to one study, the absence of MGMT promoter methylation (MGMT-unmet) predicts greater cognitive deficit when patients are treated with radiochemotherapy.22 The MGMT-met therefore can be considered a predictive marker for development of cognitive impairment, but further research about its role in cognitive functioning as well as the prognosis needed.