MGMT and glioblastoma: Gene therapy using mutant MGMT (P140K) gene-modified hematopoietic stem cells can reduce the toxic effects of chemotherapy on hematopoietic cells, and autologous P140K-modified hematopoietic stem cells transplantation has been used in glioblastoma patients with poor prognosis prior to administration of multiple cycles of chemotherapy, resulting in increase of survival without adverse effects (88).