MGMT and glioblastoma: Notably, this panel of cell cultures include all three glioblastoma subtypes, cultures with significantly variable baseline TMZ sensitivity and cell cultures with (A172, LN 229) and without (T98G, GBM6, GBM118 and GBM126) methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter, indicating miR-34a can potentially counteract heterogeneity and treatment resistance.