MGMT and pituitary tumor: MGMT downregulation was observed in a significant subset of PCs and invasive PAs, independently of the type of secreted hormones.[40] These data were corroborated in another study showing MGMT promoter methylation in a significant portion of PCs independently of endocrine activity.[12] Because methylation status was not always concordant with MGMT expression in the same samples, the molecular mechanisms underlying MGMT activity in pituitary tumors remain unknown.