MGMT and glioblastoma: The three clusters represented by different colors are as follows: 1) Mechanism in red: glioblastoma, expression, MGMT, proliferation, and o-6-methylguanine-DNA methyltransferase; 2) Clinic treatment in yellow: TMZ, chemotherapy, therapy, immunotherapy, and combination; 3) Drug design in blue: radiotherapy, adjuvant TMZ, bevacizumab, and survival.