Abstract

Objective: To analyze the reliability and reproducibility of PCR-based testing of O6-methylguanine-DNA methyltransferase gene (MGMT) promoter methylation status in formalin-fixed and paraffin-embedded (FFPE) neurosurgical biopsy specimens. Materials: We used 6 FFPE neurosurgical temporal lobe specimens of children and young adults with drug-resistant epilepsy. Histopathologically, all specimens showed CNS tissue with gliosis but no tumor tissue. Methods: For MGMT promoter methylation analysis, we used methylation specific PCR (MGMT MSP). In all 6 tissue specimens, 4 repetitive runs of MGMT MSP were performed. Results: We obtained conclusive results only in 13/24 (54.2%) MGMT MSP analyses. In 5/13 (38.5%) successful MSP runs, the results indicated presence of a methylated MGMT promoter. In only 1/6 specimens, MSP yielded consistent results in all 4 repetitive runs. Conclusions: In our hands, MGMT MSP shows poor reliability and reproducibility of test results on FFPE neurosurgical tissue specimens. A more reliable method for diagnostic MGMT promoter methylation testing needs to be identified and validated by systematic testing of intra- and interlaboratory reliability and reproducibility. Alternatively, methods of tissue fixation that do not impair DNA quality but at the same time warrant high quality histopathology could facilitate molecular diagnostics.

Author Details

Authors

• M. Preusser¹
• L. Elezi²
• J.A. Hainfellner²

Departments

• ¹ Department of Internal Medicine I, Medical University,
• ² Institute of Neurology, Medical University of Vienna, Austria

Address

J.A. Hainfellner, MD; Institute of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
Email: [email protected]

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