MGMT and glioblastoma: siMGMT silenced MGMT expression in GBM, thereby enhancing GBM sensitivity to TMZ.658 In addition, STAT3, a major gene responsible for tumor cell proliferation and resistance to apoptosis,659 can enhance GBM resistance to TMZ by upregulating MGMT expression.660 Therefore, downregulating STAT3 expression can also indirectly improve the sensitivity of GBM to TMZ.