In temozolomide-resistant glioma cells, a correlation between mutant TP53 and MGMT (O6-methylguanine DNA-methyl-transferase) was observed. While temozolomide kills cells by alkylating O6-guanine, MGMT in turn repairs alkylation. Therefore drug resistance may be caused by MGMT up-regulation. This evidence concerns the gene TP53 and central nervous system cancer.