MGMT promoter methylation correlates with an overall survival benefit in Chinese high-grade glioblastoma patients treated with radiotherapy and alkylating agent-based chemotherapy: a single-institution study

Abstract

Promoter methylation of the O(6)-methylguanine-DNA-methyltransferase (MGMT) gene has been considered a prognostic marker and has become more important in the treatment of glioblastoma. However, reports on the correlation between MGMT and clinical outcomes in Chinese glioblastoma patients are very scarce. In this study, quantitative methylation data were obtained by the pyrosequencing of tumor tissues from 128 GBM patients. The median overall survival (OS) was 13.1 months, with a 1-year survival of 45.3%. The pyrosequencing data were reproducible based on archived samples yielding data for all glioblastomas. MGMT promoter methylation was detected in 75/128 cases (58.6%), whereas 53/128 (41.4%) cases were unmethylated. Further survival analysis also revealed that methylation was an independent prognostic factor associated with prolonged OS but not with progression-free survival (PFS) (p = 0.029 and p = 0.112, respectively); the hazard radios were 0.63 (95% CI: 0.42-0.96) and 0.72 (95% CI: 0.48-1.09), respectively. These data indicated that MGMT methylation has prognostic significance in patients with newly diagnosed high-grade glioblastoma undergoing alkylating agent-based chemotherapy after surgical resection.

Figure 1. PFS after treatment in patients with methylated and unmethylated MGMT promoter glioblastomas (log-rank P = 0.112).

Figure 2. OS after treatment in patients with methylated and unmethylated MGMT promoter glioblastomas (log-rank P = 0.029).