MGMT and malignant glioma: Temozolomide is an alkylating chemotherapeutic agent that methylates DNA to counteract the effects of MGMT and is currently used in the treatment of malignant gliomas.58 Studies have suggested that there may be a role for temozolomide (TMZ) therapy in aggressive PitNETs with unmethylated MGMT that may be prone to recurrence.34 High levels of MGMT methylation correlate with poor response to TMZ in metastatic PitNETs, similar to what is observed in gliomas58,59 However, MGMT staining does not correlate with temozolamide response as closely in PitNETs.