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JPTM > Volume 45(5); 2011 > Article
The Korean Journal of Pathology 2011;45(5): 455-462.
doi: https://doi.org/10.4132/KoreanJPathol.2011.45.5.455
MGMT Gene Promoter Methylation Analysis by Pyrosequencing of Brain Tumour.
Young Zoon Kim, Young Jin Song, Ki Uk Kim, Dae Cheol Kim
1Department of Neurosurgery and Division of Neurooncology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
2Department of Neurosurgery, Dong-A University College of Medicine, Busan, Korea.
3Department of Pathology, Dong-A University College of Medicine, Busan, Korea. freehand@dau.ac.kr
ABSTRACT
BACKGROUND: The aim of this study was to determine whether pyrosequencing (PSQ) might be useful to achieve O6-methyl guanine methyltransferase (MGMT) promoter methylation using 1- to 13-year-old archival tissues as a clinical biomarker in routine practice. METHODS: The study included 141 formalin-fixed paraffin-embedded (FFPE) glial tumors from the archives of the Pathology Department from 1997-2010. RESULTS: The average percentage of methylation (MP) of the 141 cases was 14.0+/-16.8%, and methylated cases were 32.3+/-14.9%. The average MP of each year did not show a linear increasing or decreasing pattern according to the age of the FFPE block (p=0.771). The average MP of methylated glioblastomas was 35.8+/-14.7%, 31.8+/-15.5% for anaplastic astrocytomas, and 22.4+/-15.1% for astrocytoma. A tendency was observed toward an increasing pattern of average MP with World Health Organization (WHO) grade (p=0.063) in astrocytic tumors. A correlation was observed between average MP and WHO grade (p=0.038) and a bimodal distribution was observed between the methylated and unmethylated cases, using a 9% cut-off value (p<0.001). CONCLUSIONS: The results showed that a quantitative approach for MGMT promoter methylation yielded a 100% success rate for FFPE tissues from archives. PSQ can be used in a retrospective trial, but the cut-off value and calculation method should be further validated.
Key Words: Glioma; MGMT; Pyrosequencing; Biomarker; Methylation