MGMT and neoplasm: Similarly, successful treatment with the alkylating chemotherapy temozolomide occurs in pNETs with low MGMT protein expression in some but not all studies,20–22 with MGMT promoter hypermethylation a possible cause.23 Despite these correlations suggesting a relationship between response and tumor biology, the relationships are imperfect, and no predictive biomarker is in current use in the clinic.