MGMT Gene Promoter Methylation Status - Assessment of Two Pyrosequencing Kits and Three Methylation-specific PCR Methods for their Predictive Capacity in Glioblastomas

Cancer Genomics Proteomics. 2018 Nov-Dec;15(6):437-446. doi: 10.21873/cgp.20102.

Abstract

Background: Although methylation of the O6-methylguanine-DNA methyltransferase (MGMT) gene promoter predicts response to temozolomide in patients with glioblastoma, no consensus exists as to which assay is best for its detection.

Materials and methods: Methylation of MGMT promoter was examined by methylation-specific polymerase chain reaction (MSP), quantitative real-time MSP, methylation-sensitive high-resolution melting analysis, and two commercial pyrosequencing (PSQ) kits. Survival was compared among 48 patients with glioblastoma according to assay results.

Results: Only PSQ and MSP significantly separated patients who benefited from temozolomide, with PSQ being the superior method. For PSQ analysis, the cut-off value that best correlated with prognostic outcome was 7% methylation of MGMT. Median survival in patients with MGMT promoter methylation above this cut-off value was 7.8 months longer compared to those with less than 7% methylation. Two-year overall survival for the two groups was 42% and 7.4%, respectively.

Conclusion: PSQ is the method of choice for MGMT promoter methylation analysis in routine clinical practice.

Keywords: MGMT gene promoter; glioblastoma; methylation; methylation-specific PCR; overall survival; pyrosequencing.

Publication types

  • Clinical Trial

MeSH terms

  • DNA Methylation*
  • DNA Modification Methylases* / genetics
  • DNA Modification Methylases* / metabolism
  • DNA Repair Enzymes* / genetics
  • DNA Repair Enzymes* / metabolism
  • DNA, Neoplasm* / genetics
  • DNA, Neoplasm* / metabolism
  • Female
  • Glioblastoma* / genetics
  • Glioblastoma* / metabolism
  • Glioblastoma* / mortality
  • Glioblastoma* / pathology
  • Humans
  • Male
  • Polymerase Chain Reaction*
  • Predictive Value of Tests
  • Promoter Regions, Genetic*
  • Reagent Kits, Diagnostic*
  • Sequence Analysis, DNA*
  • Tumor Suppressor Proteins* / genetics
  • Tumor Suppressor Proteins* / metabolism

Substances

  • DNA, Neoplasm
  • Reagent Kits, Diagnostic
  • Tumor Suppressor Proteins
  • DNA Modification Methylases
  • MGMT protein, human
  • DNA Repair Enzymes