Comparative assessment of 5 methods (methylation-specific polymerase chain reaction, MethyLight, pyrosequencing, methylation-sensitive high-resolution melting, and immunohistochemistry) to analyze O6-methylguanine-DNA-methyltranferase in a series of 100 glioblastoma patients.

Abstract

BACKGROUND:

There is a strong need to determine the best technique for O(6) -methylguanine-DNA-methyltranferase (MGMT) analysis, because MGMT status is currently used in clinical trials and occasionally in routine clinical practice for glioblastoma patients.

METHODS:

The authors compared analytical performances and predictive values of 5 techniques in a series of 100 glioblastoma patients who received standard of care treatment (Stupp protocol).

RESULTS:

MGMT promoter was considered methylated in 33%, 33%, 42%, and 60% of patients by methylation-sensitive high-resolution melting, MethyLight, pyrosequencing (with an optimal risk cutoff at 8% for the average percentage of the 5 CpGs tested), and methylation-specific polymerase chain reaction (MS-PCR), respectively. Fifty-nine percent of the samples had <23% (the optimal risk cutoff) of MGMT-positive tumor cells. The best predictive values for overall survival (OS), after adjustment for age and performance status, were obtained by pyrosequencing (hazard ratio [HR], 0.32; P < .0001), MS-PCR (HR, 0.37; P < .0001), and immunohistochemistry (HR, 0.43; P = .0005) as compared with methylation-sensitive high-resolution melting (HR, 0.52 P = .02) and MethyLight (HR, 0.6; P = .05). For progression-free survival (PFS), the best predictive values were obtained with pyrosequencing (HR, 0.35; P < .0001), methylation-sensitive high-resolution melting (HR, 0.46; P = .002), and MS-PCR (HR, 0.49; P = .002). Combining pyrosequencing and immunohistochemistry slightly improved predictive power for OS, but not for PFS. Poor reproducibility and interobserver variability were, however, observed for immunohistochemistry.

CONCLUSIONS:

Good prediction of survival in addition to high reproducibility and sensitivity made pyrosequencing the best among the 5 techniques tested in this study.

• Authors: Véronique Quillien, Audrey Lavenu, Lucie Karayan-Tapon, Catherine Carpentier, Marianne Labussière, Thierry Lesimple, Olivier Chinot, Michel Wager, Jérome Honnorat, Stephan Saikali, Frédéric Fina, Marc Sanson, Dominique Figarella-Branger
• Journal: Cancer (Cancer) Vol. 118 Issue 17 Pg. 4201-11 (Sep 01 2012) ISSN: 1097-0142 [Electronic] United States
• PMID: 22294349 (Publication Type: Comparative Study, Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 American Cancer Society.

Chemical References

• O(6)-Methylguanine-DNA Methyltransferase

Topics

• Adult
• Aged
• Brain Neoplasms (genetics)
• DNA Methylation
• Female
• Glioblastoma (genetics, mortality)
• Humans
• Male
• Middle Aged
• O(6)-Methylguanine-DNA Methyltransferase (analysis, genetics)
• Observer Variation
• Polymerase Chain Reaction (methods)
• Prognosis
• Promoter Regions, Genetic
• Reproducibility of Results
• Sensitivity and Specificity
• Treatment Outcome
• Young Adult