In 28% of glioblastomas, the MGMT DNA repair protein is deficient but the MGMT promoter is not methylated.[47] In the glioblastomas without methylated MGMT promoters, the level of microRNA miR-181d is inversely correlated with protein expression of MGMT and the direct target of miR-181d is the MGMT mRNA 3’UTR (the three prime untranslated region of MGMT mRNA).[47] Thus, in 28% of glioblastomas, increased expression of miR-181d and reduced expression of DNA repair enzyme MGMT may be a causal factor.