MGMT and glioblastoma: The analysis of the expression of MGMT has yielded conflicting results: while a low expression of MGMT correlates with a positive response to TMZ in the case of glioblastomas (21), and in small series of aggressive PitNETs (14) this has not been clearly confirmed in larger cohorts of aggressive PitNETs and carcinomas (1, 10, 12).